--- /dev/null
+/*
+ * drm_irq.c IRQ and vblank support
+ *
+ * \author Rickard E. (Rik) Faith <faith@valinux.com>
+ * \author Gareth Hughes <gareth@valinux.com>
+ */
+
+/*
+ * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
+ *
+ * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
+ * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <drm/drmP.h>
+#include "drm_trace.h"
+#include "drm_internal.h"
+
+#include <linux/interrupt.h> /* For task queue support */
+#include <linux/slab.h>
+
+#include <linux/vgaarb.h>
+#include <linux/export.h>
+
+/* Access macro for slots in vblank timestamp ringbuffer. */
+#define vblanktimestamp(dev, crtc, count) \
+ ((dev)->vblank[crtc].time[(count) % DRM_VBLANKTIME_RBSIZE])
+
+/* Retry timestamp calculation up to 3 times to satisfy
+ * drm_timestamp_precision before giving up.
+ */
+#define DRM_TIMESTAMP_MAXRETRIES 3
+
+/* Threshold in nanoseconds for detection of redundant
+ * vblank irq in drm_handle_vblank(). 1 msec should be ok.
+ */
+#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
+
+static bool
+drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
+ struct timeval *tvblank, unsigned flags);
+
+static unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */
+
+/*
+ * Default to use monotonic timestamps for wait-for-vblank and page-flip
+ * complete events.
+ */
+unsigned int drm_timestamp_monotonic = 1;
+
+static int drm_vblank_offdelay = 5000; /* Default to 5000 msecs. */
+
+module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
+module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
+module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
+
+/**
+ * drm_update_vblank_count - update the master vblank counter
+ * @dev: DRM device
+ * @crtc: counter to update
+ *
+ * Call back into the driver to update the appropriate vblank counter
+ * (specified by @crtc). Deal with wraparound, if it occurred, and
+ * update the last read value so we can deal with wraparound on the next
+ * call if necessary.
+ *
+ * Only necessary when going from off->on, to account for frames we
+ * didn't get an interrupt for.
+ *
+ * Note: caller must hold dev->vbl_lock since this reads & writes
+ * device vblank fields.
+ */
+static void drm_update_vblank_count(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ u32 cur_vblank, diff, tslot;
+ bool rc;
+ struct timeval t_vblank;
+
+ /*
+ * Interrupts were disabled prior to this call, so deal with counter
+ * wrap if needed.
+ * NOTE! It's possible we lost a full dev->max_vblank_count events
+ * here if the register is small or we had vblank interrupts off for
+ * a long time.
+ *
+ * We repeat the hardware vblank counter & timestamp query until
+ * we get consistent results. This to prevent races between gpu
+ * updating its hardware counter while we are retrieving the
+ * corresponding vblank timestamp.
+ */
+ do {
+ cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
+ rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
+ } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
+
+ /* Deal with counter wrap */
+ diff = cur_vblank - vblank->last;
+ if (cur_vblank < vblank->last) {
+ diff += dev->max_vblank_count;
+
+ DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
+ crtc, vblank->last, cur_vblank, diff);
+ }
+
+ DRM_DEBUG("updating vblank count on crtc %d, missed %d\n",
+ crtc, diff);
+
+ if (diff == 0)
+ return;
+
+ /* Reinitialize corresponding vblank timestamp if high-precision query
+ * available. Skip this step if query unsupported or failed. Will
+ * reinitialize delayed at next vblank interrupt in that case and
+ * assign 0 for now, to mark the vblanktimestamp as invalid.
+ */
+ tslot = atomic_read(&vblank->count) + diff;
+ vblanktimestamp(dev, crtc, tslot) = rc ? t_vblank : (struct timeval) {0, 0};
+
+ smp_mb__before_atomic();
+ atomic_add(diff, &vblank->count);
+ smp_mb__after_atomic();
+}
+
+/*
+ * Disable vblank irq's on crtc, make sure that last vblank count
+ * of hardware and corresponding consistent software vblank counter
+ * are preserved, even if there are any spurious vblank irq's after
+ * disable.
+ */
+static void vblank_disable_and_save(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ unsigned long irqflags;
+ u32 vblcount;
+ s64 diff_ns;
+ bool vblrc;
+ struct timeval tvblank;
+ int count = DRM_TIMESTAMP_MAXRETRIES;
+
+ /* Prevent vblank irq processing while disabling vblank irqs,
+ * so no updates of timestamps or count can happen after we've
+ * disabled. Needed to prevent races in case of delayed irq's.
+ */
+ spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
+
+ /*
+ * If the vblank interrupt was already disabled update the count
+ * and timestamp to maintain the appearance that the counter
+ * has been ticking all along until this time. This makes the
+ * count account for the entire time between drm_vblank_on() and
+ * drm_vblank_off().
+ *
+ * But only do this if precise vblank timestamps are available.
+ * Otherwise we might read a totally bogus timestamp since drivers
+ * lacking precise timestamp support rely upon sampling the system clock
+ * at vblank interrupt time. Which obviously won't work out well if the
+ * vblank interrupt is disabled.
+ */
+ if (!vblank->enabled &&
+ drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0)) {
+ drm_update_vblank_count(dev, crtc);
+ spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
+ return;
+ }
+
+ /*
+ * Only disable vblank interrupts if they're enabled. This avoids
+ * calling the ->disable_vblank() operation in atomic context with the
+ * hardware potentially runtime suspended.
+ */
+ if (vblank->enabled) {
+ dev->driver->disable_vblank(dev, crtc);
+ vblank->enabled = false;
+ }
+
+ /* No further vblank irq's will be processed after
+ * this point. Get current hardware vblank count and
+ * vblank timestamp, repeat until they are consistent.
+ *
+ * FIXME: There is still a race condition here and in
+ * drm_update_vblank_count() which can cause off-by-one
+ * reinitialization of software vblank counter. If gpu
+ * vblank counter doesn't increment exactly at the leading
+ * edge of a vblank interval, then we can lose 1 count if
+ * we happen to execute between start of vblank and the
+ * delayed gpu counter increment.
+ */
+ do {
+ vblank->last = dev->driver->get_vblank_counter(dev, crtc);
+ vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
+ } while (vblank->last != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc);
+
+ if (!count)
+ vblrc = 0;
+
+ /* Compute time difference to stored timestamp of last vblank
+ * as updated by last invocation of drm_handle_vblank() in vblank irq.
+ */
+ vblcount = atomic_read(&vblank->count);
+ diff_ns = timeval_to_ns(&tvblank) -
+ timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
+
+ /* If there is at least 1 msec difference between the last stored
+ * timestamp and tvblank, then we are currently executing our
+ * disable inside a new vblank interval, the tvblank timestamp
+ * corresponds to this new vblank interval and the irq handler
+ * for this vblank didn't run yet and won't run due to our disable.
+ * Therefore we need to do the job of drm_handle_vblank() and
+ * increment the vblank counter by one to account for this vblank.
+ *
+ * Skip this step if there isn't any high precision timestamp
+ * available. In that case we can't account for this and just
+ * hope for the best.
+ */
+ if (vblrc && (abs64(diff_ns) > 1000000)) {
+ /* Store new timestamp in ringbuffer. */
+ vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
+
+ /* Increment cooked vblank count. This also atomically commits
+ * the timestamp computed above.
+ */
+ smp_mb__before_atomic();
+ atomic_inc(&vblank->count);
+ smp_mb__after_atomic();
+ }
+
+ spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
+}
+
+static void vblank_disable_fn(unsigned long arg)
+{
+ struct drm_vblank_crtc *vblank = (void *)arg;
+ struct drm_device *dev = vblank->dev;
+ unsigned long irqflags;
+ int crtc = vblank->crtc;
+
+ if (!dev->vblank_disable_allowed)
+ return;
+
+ spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
+ DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
+ vblank_disable_and_save(dev, crtc);
+ }
+ spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+}
+
+/**
+ * drm_vblank_cleanup - cleanup vblank support
+ * @dev: DRM device
+ *
+ * This function cleans up any resources allocated in drm_vblank_init.
+ */
+void drm_vblank_cleanup(struct drm_device *dev)
+{
+ int crtc;
+
+ /* Bail if the driver didn't call drm_vblank_init() */
+ if (dev->num_crtcs == 0)
+ return;
+
+ for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+
+ WARN_ON(vblank->enabled &&
+ drm_core_check_feature(dev, DRIVER_MODESET));
+
+ del_timer_sync(&vblank->disable_timer);
+ }
+
+ kfree(dev->vblank);
+
+ dev->num_crtcs = 0;
+}
+EXPORT_SYMBOL(drm_vblank_cleanup);
+
+/**
+ * drm_vblank_init - initialize vblank support
+ * @dev: drm_device
+ * @num_crtcs: number of crtcs supported by @dev
+ *
+ * This function initializes vblank support for @num_crtcs display pipelines.
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+int drm_vblank_init(struct drm_device *dev, int num_crtcs)
+{
+ int i, ret = -ENOMEM;
+
+ spin_lock_init(&dev->vbl_lock);
+ spin_lock_init(&dev->vblank_time_lock);
+
+ dev->num_crtcs = num_crtcs;
+
+ dev->vblank = kcalloc(num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
+ if (!dev->vblank)
+ goto err;
+
+ for (i = 0; i < num_crtcs; i++) {
+ struct drm_vblank_crtc *vblank = &dev->vblank[i];
+
+ vblank->dev = dev;
+ vblank->crtc = i;
+ init_waitqueue_head(&vblank->queue);
+ setup_timer(&vblank->disable_timer, vblank_disable_fn,
+ (unsigned long)vblank);
+ }
+
+ DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
+
+ /* Driver specific high-precision vblank timestamping supported? */
+ if (dev->driver->get_vblank_timestamp)
+ DRM_INFO("Driver supports precise vblank timestamp query.\n");
+ else
+ DRM_INFO("No driver support for vblank timestamp query.\n");
+
+ dev->vblank_disable_allowed = false;
+
+ return 0;
+
+err:
+ dev->num_crtcs = 0;
+ return ret;
+}
+EXPORT_SYMBOL(drm_vblank_init);
+
+static void drm_irq_vgaarb_nokms(void *cookie, bool state)
+{
+ struct drm_device *dev = cookie;
+
+ if (dev->driver->vgaarb_irq) {
+ dev->driver->vgaarb_irq(dev, state);
+ return;
+ }
+
+ if (!dev->irq_enabled)
+ return;
+
+ if (state) {
+ if (dev->driver->irq_uninstall)
+ dev->driver->irq_uninstall(dev);
+ } else {
+ if (dev->driver->irq_preinstall)
+ dev->driver->irq_preinstall(dev);
+ if (dev->driver->irq_postinstall)
+ dev->driver->irq_postinstall(dev);
+ }
+}
+
+/**
+ * drm_irq_install - install IRQ handler
+ * @dev: DRM device
+ * @irq: IRQ number to install the handler for
+ *
+ * Initializes the IRQ related data. Installs the handler, calling the driver
+ * irq_preinstall() and irq_postinstall() functions before and after the
+ * installation.
+ *
+ * This is the simplified helper interface provided for drivers with no special
+ * needs. Drivers which need to install interrupt handlers for multiple
+ * interrupts must instead set drm_device->irq_enabled to signal the DRM core
+ * that vblank interrupts are available.
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+int drm_irq_install(struct drm_device *dev, int irq)
+{
+ int ret;
+ unsigned long sh_flags = 0;
+
+ if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
+ return -EINVAL;
+
+ if (irq == 0)
+ return -EINVAL;
+
+ /* Driver must have been initialized */
+ if (!dev->dev_private)
+ return -EINVAL;
+
+ if (dev->irq_enabled)
+ return -EBUSY;
+ dev->irq_enabled = true;
+
+ DRM_DEBUG("irq=%d\n", irq);
+
+ /* Before installing handler */
+ if (dev->driver->irq_preinstall)
+ dev->driver->irq_preinstall(dev);
+
+ /* Install handler */
+ if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
+ sh_flags = IRQF_SHARED;
+
+ ret = request_irq(irq, dev->driver->irq_handler,
+ sh_flags, dev->driver->name, dev);
+
+ if (ret < 0) {
+ dev->irq_enabled = false;
+ return ret;
+ }
+
+ if (!drm_core_check_feature(dev, DRIVER_MODESET))
+ vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
+
+ /* After installing handler */
+ if (dev->driver->irq_postinstall)
+ ret = dev->driver->irq_postinstall(dev);
+
+ if (ret < 0) {
+ dev->irq_enabled = false;
+ if (!drm_core_check_feature(dev, DRIVER_MODESET))
+ vga_client_register(dev->pdev, NULL, NULL, NULL);
+ free_irq(irq, dev);
+ } else {
+ dev->irq = irq;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(drm_irq_install);
+
+/**
+ * drm_irq_uninstall - uninstall the IRQ handler
+ * @dev: DRM device
+ *
+ * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
+ * This should only be called by drivers which used drm_irq_install() to set up
+ * their interrupt handler. Other drivers must only reset
+ * drm_device->irq_enabled to false.
+ *
+ * Note that for kernel modesetting drivers it is a bug if this function fails.
+ * The sanity checks are only to catch buggy user modesetting drivers which call
+ * the same function through an ioctl.
+ *
+ * Returns:
+ * Zero on success or a negative error code on failure.
+ */
+int drm_irq_uninstall(struct drm_device *dev)
+{
+ unsigned long irqflags;
+ bool irq_enabled;
+ int i;
+
+ if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
+ return -EINVAL;
+
+ irq_enabled = dev->irq_enabled;
+ dev->irq_enabled = false;
+
+ /*
+ * Wake up any waiters so they don't hang. This is just to paper over
+ * isssues for UMS drivers which aren't in full control of their
+ * vblank/irq handling. KMS drivers must ensure that vblanks are all
+ * disabled when uninstalling the irq handler.
+ */
+ if (dev->num_crtcs) {
+ spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ for (i = 0; i < dev->num_crtcs; i++) {
+ struct drm_vblank_crtc *vblank = &dev->vblank[i];
+
+ if (!vblank->enabled)
+ continue;
+
+ WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));
+
+ vblank_disable_and_save(dev, i);
+ wake_up(&vblank->queue);
+ }
+ spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+ }
+
+ if (!irq_enabled)
+ return -EINVAL;
+
+ DRM_DEBUG("irq=%d\n", dev->irq);
+
+ if (!drm_core_check_feature(dev, DRIVER_MODESET))
+ vga_client_register(dev->pdev, NULL, NULL, NULL);
+
+ if (dev->driver->irq_uninstall)
+ dev->driver->irq_uninstall(dev);
+
+ free_irq(dev->irq, dev);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_irq_uninstall);
+
+/*
+ * IRQ control ioctl.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_control structure.
+ * \return zero on success or a negative number on failure.
+ *
+ * Calls irq_install() or irq_uninstall() according to \p arg.
+ */
+int drm_control(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_control *ctl = data;
+ int ret = 0, irq;
+
+ /* if we haven't irq we fallback for compatibility reasons -
+ * this used to be a separate function in drm_dma.h
+ */
+
+ if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
+ return 0;
+ if (drm_core_check_feature(dev, DRIVER_MODESET))
+ return 0;
+ /* UMS was only ever support on pci devices. */
+ if (WARN_ON(!dev->pdev))
+ return -EINVAL;
+
+ switch (ctl->func) {
+ case DRM_INST_HANDLER:
+ irq = dev->pdev->irq;
+
+ if (dev->if_version < DRM_IF_VERSION(1, 2) &&
+ ctl->irq != irq)
+ return -EINVAL;
+ mutex_lock(&dev->struct_mutex);
+ ret = drm_irq_install(dev, irq);
+ mutex_unlock(&dev->struct_mutex);
+
+ return ret;
+ case DRM_UNINST_HANDLER:
+ mutex_lock(&dev->struct_mutex);
+ ret = drm_irq_uninstall(dev);
+ mutex_unlock(&dev->struct_mutex);
+
+ return ret;
+ default:
+ return -EINVAL;
+ }
+}
+
+/**
+ * drm_calc_timestamping_constants - calculate vblank timestamp constants
+ * @crtc: drm_crtc whose timestamp constants should be updated.
+ * @mode: display mode containing the scanout timings
+ *
+ * Calculate and store various constants which are later
+ * needed by vblank and swap-completion timestamping, e.g,
+ * by drm_calc_vbltimestamp_from_scanoutpos(). They are
+ * derived from CRTC's true scanout timing, so they take
+ * things like panel scaling or other adjustments into account.
+ */
+void drm_calc_timestamping_constants(struct drm_crtc *crtc,
+ const struct drm_display_mode *mode)
+{
+ int linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
+ int dotclock = mode->crtc_clock;
+
+ /* Valid dotclock? */
+ if (dotclock > 0) {
+ int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
+
+ /*
+ * Convert scanline length in pixels and video
+ * dot clock to line duration, frame duration
+ * and pixel duration in nanoseconds:
+ */
+ pixeldur_ns = 1000000 / dotclock;
+ linedur_ns = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
+ framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
+
+ /*
+ * Fields of interlaced scanout modes are only half a frame duration.
+ */
+ if (mode->flags & DRM_MODE_FLAG_INTERLACE)
+ framedur_ns /= 2;
+ } else
+ DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
+ crtc->base.id);
+
+ crtc->pixeldur_ns = pixeldur_ns;
+ crtc->linedur_ns = linedur_ns;
+ crtc->framedur_ns = framedur_ns;
+
+ DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
+ crtc->base.id, mode->crtc_htotal,
+ mode->crtc_vtotal, mode->crtc_vdisplay);
+ DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
+ crtc->base.id, dotclock, framedur_ns,
+ linedur_ns, pixeldur_ns);
+}
+EXPORT_SYMBOL(drm_calc_timestamping_constants);
+
+/**
+ * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
+ * @dev: DRM device
+ * @crtc: Which CRTC's vblank timestamp to retrieve
+ * @max_error: Desired maximum allowable error in timestamps (nanosecs)
+ * On return contains true maximum error of timestamp
+ * @vblank_time: Pointer to struct timeval which should receive the timestamp
+ * @flags: Flags to pass to driver:
+ * 0 = Default,
+ * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
+ * @refcrtc: CRTC which defines scanout timing
+ * @mode: mode which defines the scanout timings
+ *
+ * Implements calculation of exact vblank timestamps from given drm_display_mode
+ * timings and current video scanout position of a CRTC. This can be called from
+ * within get_vblank_timestamp() implementation of a kms driver to implement the
+ * actual timestamping.
+ *
+ * Should return timestamps conforming to the OML_sync_control OpenML
+ * extension specification. The timestamp corresponds to the end of
+ * the vblank interval, aka start of scanout of topmost-leftmost display
+ * pixel in the following video frame.
+ *
+ * Requires support for optional dev->driver->get_scanout_position()
+ * in kms driver, plus a bit of setup code to provide a drm_display_mode
+ * that corresponds to the true scanout timing.
+ *
+ * The current implementation only handles standard video modes. It
+ * returns as no operation if a doublescan or interlaced video mode is
+ * active. Higher level code is expected to handle this.
+ *
+ * Returns:
+ * Negative value on error, failure or if not supported in current
+ * video mode:
+ *
+ * -EINVAL - Invalid CRTC.
+ * -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
+ * -ENOTSUPP - Function not supported in current display mode.
+ * -EIO - Failed, e.g., due to failed scanout position query.
+ *
+ * Returns or'ed positive status flags on success:
+ *
+ * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
+ * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
+ *
+ */
+int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
+ int *max_error,
+ struct timeval *vblank_time,
+ unsigned flags,
+ const struct drm_crtc *refcrtc,
+ const struct drm_display_mode *mode)
+{
+ struct timeval tv_etime;
+ ktime_t stime, etime;
+ int vbl_status;
+ int vpos, hpos, i;
+ int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
+ bool invbl;
+
+ if (crtc < 0 || crtc >= dev->num_crtcs) {
+ DRM_ERROR("Invalid crtc %d\n", crtc);
+ return -EINVAL;
+ }
+
+ /* Scanout position query not supported? Should not happen. */
+ if (!dev->driver->get_scanout_position) {
+ DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
+ return -EIO;
+ }
+
+ /* Durations of frames, lines, pixels in nanoseconds. */
+ framedur_ns = refcrtc->framedur_ns;
+ linedur_ns = refcrtc->linedur_ns;
+ pixeldur_ns = refcrtc->pixeldur_ns;
+
+ /* If mode timing undefined, just return as no-op:
+ * Happens during initial modesetting of a crtc.
+ */
+ if (framedur_ns == 0) {
+ DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
+ return -EAGAIN;
+ }
+
+ /* Get current scanout position with system timestamp.
+ * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
+ * if single query takes longer than max_error nanoseconds.
+ *
+ * This guarantees a tight bound on maximum error if
+ * code gets preempted or delayed for some reason.
+ */
+ for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
+ /*
+ * Get vertical and horizontal scanout position vpos, hpos,
+ * and bounding timestamps stime, etime, pre/post query.
+ */
+ vbl_status = dev->driver->get_scanout_position(dev, crtc, flags, &vpos,
+ &hpos, &stime, &etime);
+
+ /* Return as no-op if scanout query unsupported or failed. */
+ if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
+ DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
+ crtc, vbl_status);
+ return -EIO;
+ }
+
+ /* Compute uncertainty in timestamp of scanout position query. */
+ duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
+
+ /* Accept result with < max_error nsecs timing uncertainty. */
+ if (duration_ns <= *max_error)
+ break;
+ }
+
+ /* Noisy system timing? */
+ if (i == DRM_TIMESTAMP_MAXRETRIES) {
+ DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
+ crtc, duration_ns/1000, *max_error/1000, i);
+ }
+
+ /* Return upper bound of timestamp precision error. */
+ *max_error = duration_ns;
+
+ /* Check if in vblank area:
+ * vpos is >=0 in video scanout area, but negative
+ * within vblank area, counting down the number of lines until
+ * start of scanout.
+ */
+ invbl = vbl_status & DRM_SCANOUTPOS_IN_VBLANK;
+
+ /* Convert scanout position into elapsed time at raw_time query
+ * since start of scanout at first display scanline. delta_ns
+ * can be negative if start of scanout hasn't happened yet.
+ */
+ delta_ns = vpos * linedur_ns + hpos * pixeldur_ns;
+
+ if (!drm_timestamp_monotonic)
+ etime = ktime_mono_to_real(etime);
+
+ /* save this only for debugging purposes */
+ tv_etime = ktime_to_timeval(etime);
+ /* Subtract time delta from raw timestamp to get final
+ * vblank_time timestamp for end of vblank.
+ */
+ if (delta_ns < 0)
+ etime = ktime_add_ns(etime, -delta_ns);
+ else
+ etime = ktime_sub_ns(etime, delta_ns);
+ *vblank_time = ktime_to_timeval(etime);
+
+ DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
+ crtc, (int)vbl_status, hpos, vpos,
+ (long)tv_etime.tv_sec, (long)tv_etime.tv_usec,
+ (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
+ duration_ns/1000, i);
+
+ vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
+ if (invbl)
+ vbl_status |= DRM_VBLANKTIME_IN_VBLANK;
+
+ return vbl_status;
+}
+EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
+
+static struct timeval get_drm_timestamp(void)
+{
+ ktime_t now;
+
+ now = drm_timestamp_monotonic ? ktime_get() : ktime_get_real();
+ return ktime_to_timeval(now);
+}
+
+/**
+ * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
+ * vblank interval
+ * @dev: DRM device
+ * @crtc: which CRTC's vblank timestamp to retrieve
+ * @tvblank: Pointer to target struct timeval which should receive the timestamp
+ * @flags: Flags to pass to driver:
+ * 0 = Default,
+ * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
+ *
+ * Fetches the system timestamp corresponding to the time of the most recent
+ * vblank interval on specified CRTC. May call into kms-driver to
+ * compute the timestamp with a high-precision GPU specific method.
+ *
+ * Returns zero if timestamp originates from uncorrected do_gettimeofday()
+ * call, i.e., it isn't very precisely locked to the true vblank.
+ *
+ * Returns:
+ * True if timestamp is considered to be very precise, false otherwise.
+ */
+static bool
+drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
+ struct timeval *tvblank, unsigned flags)
+{
+ int ret;
+
+ /* Define requested maximum error on timestamps (nanoseconds). */
+ int max_error = (int) drm_timestamp_precision * 1000;
+
+ /* Query driver if possible and precision timestamping enabled. */
+ if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
+ ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
+ tvblank, flags);
+ if (ret > 0)
+ return true;
+ }
+
+ /* GPU high precision timestamp query unsupported or failed.
+ * Return current monotonic/gettimeofday timestamp as best estimate.
+ */
+ *tvblank = get_drm_timestamp();
+
+ return false;
+}
+
+/**
+ * drm_vblank_count - retrieve "cooked" vblank counter value
+ * @dev: DRM device
+ * @crtc: which counter to retrieve
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity.
+ *
+ * This is the legacy version of drm_crtc_vblank_count().
+ *
+ * Returns:
+ * The software vblank counter.
+ */
+u32 drm_vblank_count(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return 0;
+ return atomic_read(&vblank->count);
+}
+EXPORT_SYMBOL(drm_vblank_count);
+
+/**
+ * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
+ * @crtc: which counter to retrieve
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity.
+ *
+ * This is the native KMS version of drm_vblank_count().
+ *
+ * Returns:
+ * The software vblank counter.
+ */
+u32 drm_crtc_vblank_count(struct drm_crtc *crtc)
+{
+ return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_count);
+
+/**
+ * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
+ * and the system timestamp corresponding to that vblank counter value.
+ *
+ * @dev: DRM device
+ * @crtc: which counter to retrieve
+ * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity. Returns corresponding system timestamp of the time
+ * of the vblank interval that corresponds to the current vblank counter value.
+ */
+u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
+ struct timeval *vblanktime)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ u32 cur_vblank;
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return 0;
+
+ /* Read timestamp from slot of _vblank_time ringbuffer
+ * that corresponds to current vblank count. Retry if
+ * count has incremented during readout. This works like
+ * a seqlock.
+ */
+ do {
+ cur_vblank = atomic_read(&vblank->count);
+ *vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
+ smp_rmb();
+ } while (cur_vblank != atomic_read(&vblank->count));
+
+ return cur_vblank;
+}
+EXPORT_SYMBOL(drm_vblank_count_and_time);
+
+static void send_vblank_event(struct drm_device *dev,
+ struct drm_pending_vblank_event *e,
+ unsigned long seq, struct timeval *now)
+{
+ WARN_ON_SMP(!spin_is_locked(&dev->event_lock));
+ e->event.sequence = seq;
+ e->event.tv_sec = now->tv_sec;
+ e->event.tv_usec = now->tv_usec;
+
+ list_add_tail(&e->base.link,
+ &e->base.file_priv->event_list);
+ wake_up_interruptible(&e->base.file_priv->event_wait);
+ trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
+ e->event.sequence);
+}
+
+/**
+ * drm_send_vblank_event - helper to send vblank event after pageflip
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ * @e: the event to send
+ *
+ * Updates sequence # and timestamp on event, and sends it to userspace.
+ * Caller must hold event lock.
+ *
+ * This is the legacy version of drm_crtc_send_vblank_event().
+ */
+void drm_send_vblank_event(struct drm_device *dev, int crtc,
+ struct drm_pending_vblank_event *e)
+{
+ struct timeval now;
+ unsigned int seq;
+
+ if (crtc >= 0) {
+ seq = drm_vblank_count_and_time(dev, crtc, &now);
+ } else {
+ seq = 0;
+
+ now = get_drm_timestamp();
+ }
+ e->pipe = crtc;
+ send_vblank_event(dev, e, seq, &now);
+}
+EXPORT_SYMBOL(drm_send_vblank_event);
+
+/**
+ * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
+ * @crtc: the source CRTC of the vblank event
+ * @e: the event to send
+ *
+ * Updates sequence # and timestamp on event, and sends it to userspace.
+ * Caller must hold event lock.
+ *
+ * This is the native KMS version of drm_send_vblank_event().
+ */
+void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
+ struct drm_pending_vblank_event *e)
+{
+ drm_send_vblank_event(crtc->dev, drm_crtc_index(crtc), e);
+}
+EXPORT_SYMBOL(drm_crtc_send_vblank_event);
+
+/**
+ * drm_vblank_enable - enable the vblank interrupt on a CRTC
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ */
+static int drm_vblank_enable(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ int ret = 0;
+
+ assert_spin_locked(&dev->vbl_lock);
+
+ spin_lock(&dev->vblank_time_lock);
+
+ if (!vblank->enabled) {
+ /*
+ * Enable vblank irqs under vblank_time_lock protection.
+ * All vblank count & timestamp updates are held off
+ * until we are done reinitializing master counter and
+ * timestamps. Filtercode in drm_handle_vblank() will
+ * prevent double-accounting of same vblank interval.
+ */
+ ret = dev->driver->enable_vblank(dev, crtc);
+ DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
+ if (ret)
+ atomic_dec(&vblank->refcount);
+ else {
+ vblank->enabled = true;
+ drm_update_vblank_count(dev, crtc);
+ }
+ }
+
+ spin_unlock(&dev->vblank_time_lock);
+
+ return ret;
+}
+
+/**
+ * drm_vblank_get - get a reference count on vblank events
+ * @dev: DRM device
+ * @crtc: which CRTC to own
+ *
+ * Acquire a reference count on vblank events to avoid having them disabled
+ * while in use.
+ *
+ * This is the legacy version of drm_crtc_vblank_get().
+ *
+ * Returns:
+ * Zero on success, nonzero on failure.
+ */
+int drm_vblank_get(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ unsigned long irqflags;
+ int ret = 0;
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return -EINVAL;
+
+ spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ /* Going from 0->1 means we have to enable interrupts again */
+ if (atomic_add_return(1, &vblank->refcount) == 1) {
+ ret = drm_vblank_enable(dev, crtc);
+ } else {
+ if (!vblank->enabled) {
+ atomic_dec(&vblank->refcount);
+ ret = -EINVAL;
+ }
+ }
+ spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+ return ret;
+}
+EXPORT_SYMBOL(drm_vblank_get);
+
+/**
+ * drm_crtc_vblank_get - get a reference count on vblank events
+ * @crtc: which CRTC to own
+ *
+ * Acquire a reference count on vblank events to avoid having them disabled
+ * while in use.
+ *
+ * This is the native kms version of drm_vblank_get().
+ *
+ * Returns:
+ * Zero on success, nonzero on failure.
+ */
+int drm_crtc_vblank_get(struct drm_crtc *crtc)
+{
+ return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_get);
+
+/**
+ * drm_vblank_put - give up ownership of vblank events
+ * @dev: DRM device
+ * @crtc: which counter to give up
+ *
+ * Release ownership of a given vblank counter, turning off interrupts
+ * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
+ *
+ * This is the legacy version of drm_crtc_vblank_put().
+ */
+void drm_vblank_put(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+
+ if (WARN_ON(atomic_read(&vblank->refcount) == 0))
+ return;
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return;
+
+ /* Last user schedules interrupt disable */
+ if (atomic_dec_and_test(&vblank->refcount)) {
+ if (drm_vblank_offdelay == 0)
+ return;
+ else if (dev->vblank_disable_immediate || drm_vblank_offdelay < 0)
+ vblank_disable_fn((unsigned long)vblank);
+ else
+ mod_timer(&vblank->disable_timer,
+ jiffies + ((drm_vblank_offdelay * HZ)/1000));
+ }
+}
+EXPORT_SYMBOL(drm_vblank_put);
+
+/**
+ * drm_crtc_vblank_put - give up ownership of vblank events
+ * @crtc: which counter to give up
+ *
+ * Release ownership of a given vblank counter, turning off interrupts
+ * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
+ *
+ * This is the native kms version of drm_vblank_put().
+ */
+void drm_crtc_vblank_put(struct drm_crtc *crtc)
+{
+ drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_put);
+
+/**
+ * drm_wait_one_vblank - wait for one vblank
+ * @dev: DRM device
+ * @crtc: crtc index
+ *
+ * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
+ * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
+ * due to lack of driver support or because the crtc is off.
+ */
+void drm_wait_one_vblank(struct drm_device *dev, int crtc)
+{
+ int ret;
+ u32 last;
+
+ ret = drm_vblank_get(dev, crtc);
+ if (WARN(ret, "vblank not available on crtc %i, ret=%i\n", crtc, ret))
+ return;
+
+ last = drm_vblank_count(dev, crtc);
+
+ ret = wait_event_timeout(dev->vblank[crtc].queue,
+ last != drm_vblank_count(dev, crtc),
+ msecs_to_jiffies(100));
+
+ WARN(ret == 0, "vblank wait timed out on crtc %i\n", crtc);
+
+ drm_vblank_put(dev, crtc);
+}
+EXPORT_SYMBOL(drm_wait_one_vblank);
+
+/**
+ * drm_crtc_wait_one_vblank - wait for one vblank
+ * @crtc: DRM crtc
+ *
+ * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
+ * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
+ * due to lack of driver support or because the crtc is off.
+ */
+void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
+{
+ drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
+
+/**
+ * drm_vblank_off - disable vblank events on a CRTC
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ *
+ * Drivers can use this function to shut down the vblank interrupt handling when
+ * disabling a crtc. This function ensures that the latest vblank frame count is
+ * stored so that drm_vblank_on() can restore it again.
+ *
+ * Drivers must use this function when the hardware vblank counter can get
+ * reset, e.g. when suspending.
+ *
+ * This is the legacy version of drm_crtc_vblank_off().
+ */
+void drm_vblank_off(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ struct drm_pending_vblank_event *e, *t;
+ struct timeval now;
+ unsigned long irqflags;
+ unsigned int seq;
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return;
+
+ spin_lock_irqsave(&dev->event_lock, irqflags);
+
+ spin_lock(&dev->vbl_lock);
+ vblank_disable_and_save(dev, crtc);
+ wake_up(&vblank->queue);
+
+ /*
+ * Prevent subsequent drm_vblank_get() from re-enabling
+ * the vblank interrupt by bumping the refcount.
+ */
+ if (!vblank->inmodeset) {
+ atomic_inc(&vblank->refcount);
+ vblank->inmodeset = 1;
+ }
+ spin_unlock(&dev->vbl_lock);
+
+ /* Send any queued vblank events, lest the natives grow disquiet */
+ seq = drm_vblank_count_and_time(dev, crtc, &now);
+
+ list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
+ if (e->pipe != crtc)
+ continue;
+ DRM_DEBUG("Sending premature vblank event on disable: \
+ wanted %d, current %d\n",
+ e->event.sequence, seq);
+ list_del(&e->base.link);
+ drm_vblank_put(dev, e->pipe);
+ send_vblank_event(dev, e, seq, &now);
+ }
+ spin_unlock_irqrestore(&dev->event_lock, irqflags);
+}
+EXPORT_SYMBOL(drm_vblank_off);
+
+/**
+ * drm_crtc_vblank_off - disable vblank events on a CRTC
+ * @crtc: CRTC in question
+ *
+ * Drivers can use this function to shut down the vblank interrupt handling when
+ * disabling a crtc. This function ensures that the latest vblank frame count is
+ * stored so that drm_vblank_on can restore it again.
+ *
+ * Drivers must use this function when the hardware vblank counter can get
+ * reset, e.g. when suspending.
+ *
+ * This is the native kms version of drm_vblank_off().
+ */
+void drm_crtc_vblank_off(struct drm_crtc *crtc)
+{
+ drm_vblank_off(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_off);
+
+/**
+ * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
+ * @crtc: CRTC in question
+ *
+ * Drivers can use this function to reset the vblank state to off at load time.
+ * Drivers should use this together with the drm_crtc_vblank_off() and
+ * drm_crtc_vblank_on() functions. The difference compared to
+ * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
+ * and hence doesn't need to call any driver hooks.
+ */
+void drm_crtc_vblank_reset(struct drm_crtc *drm_crtc)
+{
+ struct drm_device *dev = drm_crtc->dev;
+ unsigned long irqflags;
+ int crtc = drm_crtc_index(drm_crtc);
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+
+ spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ /*
+ * Prevent subsequent drm_vblank_get() from enabling the vblank
+ * interrupt by bumping the refcount.
+ */
+ if (!vblank->inmodeset) {
+ atomic_inc(&vblank->refcount);
+ vblank->inmodeset = 1;
+ }
+ spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+ WARN_ON(!list_empty(&dev->vblank_event_list));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_reset);
+
+/**
+ * drm_vblank_on - enable vblank events on a CRTC
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ *
+ * This functions restores the vblank interrupt state captured with
+ * drm_vblank_off() again. Note that calls to drm_vblank_on() and
+ * drm_vblank_off() can be unbalanced and so can also be unconditionally called
+ * in driver load code to reflect the current hardware state of the crtc.
+ *
+ * This is the legacy version of drm_crtc_vblank_on().
+ */
+void drm_vblank_on(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ unsigned long irqflags;
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return;
+
+ spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ /* Drop our private "prevent drm_vblank_get" refcount */
+ if (vblank->inmodeset) {
+ atomic_dec(&vblank->refcount);
+ vblank->inmodeset = 0;
+ }
+
+ /*
+ * sample the current counter to avoid random jumps
+ * when drm_vblank_enable() applies the diff
+ *
+ * -1 to make sure user will never see the same
+ * vblank counter value before and after a modeset
+ */
+ vblank->last =
+ (dev->driver->get_vblank_counter(dev, crtc) - 1) &
+ dev->max_vblank_count;
+ /*
+ * re-enable interrupts if there are users left, or the
+ * user wishes vblank interrupts to be enabled all the time.
+ */
+ if (atomic_read(&vblank->refcount) != 0 ||
+ (!dev->vblank_disable_immediate && drm_vblank_offdelay == 0))
+ WARN_ON(drm_vblank_enable(dev, crtc));
+ spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+}
+EXPORT_SYMBOL(drm_vblank_on);
+
+/**
+ * drm_crtc_vblank_on - enable vblank events on a CRTC
+ * @crtc: CRTC in question
+ *
+ * This functions restores the vblank interrupt state captured with
+ * drm_vblank_off() again. Note that calls to drm_vblank_on() and
+ * drm_vblank_off() can be unbalanced and so can also be unconditionally called
+ * in driver load code to reflect the current hardware state of the crtc.
+ *
+ * This is the native kms version of drm_vblank_on().
+ */
+void drm_crtc_vblank_on(struct drm_crtc *crtc)
+{
+ drm_vblank_on(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_vblank_on);
+
+/**
+ * drm_vblank_pre_modeset - account for vblanks across mode sets
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ *
+ * Account for vblank events across mode setting events, which will likely
+ * reset the hardware frame counter.
+ *
+ * This is done by grabbing a temporary vblank reference to ensure that the
+ * vblank interrupt keeps running across the modeset sequence. With this the
+ * software-side vblank frame counting will ensure that there are no jumps or
+ * discontinuities.
+ *
+ * Unfortunately this approach is racy and also doesn't work when the vblank
+ * interrupt stops running, e.g. across system suspend resume. It is therefore
+ * highly recommended that drivers use the newer drm_vblank_off() and
+ * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
+ * using "cooked" software vblank frame counters and not relying on any hardware
+ * counters.
+ *
+ * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
+ * again.
+ */
+void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+
+ /* vblank is not initialized (IRQ not installed ?), or has been freed */
+ if (!dev->num_crtcs)
+ return;
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return;
+
+ /*
+ * To avoid all the problems that might happen if interrupts
+ * were enabled/disabled around or between these calls, we just
+ * have the kernel take a reference on the CRTC (just once though
+ * to avoid corrupting the count if multiple, mismatch calls occur),
+ * so that interrupts remain enabled in the interim.
+ */
+ if (!vblank->inmodeset) {
+ vblank->inmodeset = 0x1;
+ if (drm_vblank_get(dev, crtc) == 0)
+ vblank->inmodeset |= 0x2;
+ }
+}
+EXPORT_SYMBOL(drm_vblank_pre_modeset);
+
+/**
+ * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
+ * @dev: DRM device
+ * @crtc: CRTC in question
+ *
+ * This function again drops the temporary vblank reference acquired in
+ * drm_vblank_pre_modeset.
+ */
+void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ unsigned long irqflags;
+
+ /* vblank is not initialized (IRQ not installed ?), or has been freed */
+ if (!dev->num_crtcs)
+ return;
+
+ if (vblank->inmodeset) {
+ spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ dev->vblank_disable_allowed = true;
+ spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+ if (vblank->inmodeset & 0x2)
+ drm_vblank_put(dev, crtc);
+
+ vblank->inmodeset = 0;
+ }
+}
+EXPORT_SYMBOL(drm_vblank_post_modeset);
+
+/*
+ * drm_modeset_ctl - handle vblank event counter changes across mode switch
+ * @DRM_IOCTL_ARGS: standard ioctl arguments
+ *
+ * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
+ * ioctls around modesetting so that any lost vblank events are accounted for.
+ *
+ * Generally the counter will reset across mode sets. If interrupts are
+ * enabled around this call, we don't have to do anything since the counter
+ * will have already been incremented.
+ */
+int drm_modeset_ctl(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_modeset_ctl *modeset = data;
+ unsigned int crtc;
+
+ /* If drm_vblank_init() hasn't been called yet, just no-op */
+ if (!dev->num_crtcs)
+ return 0;
+
+ /* KMS drivers handle this internally */
+ if (drm_core_check_feature(dev, DRIVER_MODESET))
+ return 0;
+
+ crtc = modeset->crtc;
+ if (crtc >= dev->num_crtcs)
+ return -EINVAL;
+
+ switch (modeset->cmd) {
+ case _DRM_PRE_MODESET:
+ drm_vblank_pre_modeset(dev, crtc);
+ break;
+ case _DRM_POST_MODESET:
+ drm_vblank_post_modeset(dev, crtc);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
+ union drm_wait_vblank *vblwait,
+ struct drm_file *file_priv)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+ struct drm_pending_vblank_event *e;
+ struct timeval now;
+ unsigned long flags;
+ unsigned int seq;
+ int ret;
+
+ e = kzalloc(sizeof(*e), GFP_KERNEL);
+ if (e == NULL) {
+ ret = -ENOMEM;
+ goto err_put;
+ }
+
+ e->pipe = pipe;
+ e->base.pid = current->pid;
+ e->event.base.type = DRM_EVENT_VBLANK;
+ e->event.base.length = sizeof(e->event);
+ e->event.user_data = vblwait->request.signal;
+ e->base.event = &e->event.base;
+ e->base.file_priv = file_priv;
+ e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
+
+ spin_lock_irqsave(&dev->event_lock, flags);
+
+ /*
+ * drm_vblank_off() might have been called after we called
+ * drm_vblank_get(). drm_vblank_off() holds event_lock
+ * around the vblank disable, so no need for further locking.
+ * The reference from drm_vblank_get() protects against
+ * vblank disable from another source.
+ */
+ if (!vblank->enabled) {
+ ret = -EINVAL;
+ goto err_unlock;
+ }
+
+ if (file_priv->event_space < sizeof(e->event)) {
+ ret = -EBUSY;
+ goto err_unlock;
+ }
+
+ file_priv->event_space -= sizeof(e->event);
+ seq = drm_vblank_count_and_time(dev, pipe, &now);
+
+ if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
+ (seq - vblwait->request.sequence) <= (1 << 23)) {
+ vblwait->request.sequence = seq + 1;
+ vblwait->reply.sequence = vblwait->request.sequence;
+ }
+
+ DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
+ vblwait->request.sequence, seq, pipe);
+
+ trace_drm_vblank_event_queued(current->pid, pipe,
+ vblwait->request.sequence);
+
+ e->event.sequence = vblwait->request.sequence;
+ if ((seq - vblwait->request.sequence) <= (1 << 23)) {
+ drm_vblank_put(dev, pipe);
+ send_vblank_event(dev, e, seq, &now);
+ vblwait->reply.sequence = seq;
+ } else {
+ /* drm_handle_vblank_events will call drm_vblank_put */
+ list_add_tail(&e->base.link, &dev->vblank_event_list);
+ vblwait->reply.sequence = vblwait->request.sequence;
+ }
+
+ spin_unlock_irqrestore(&dev->event_lock, flags);
+
+ return 0;
+
+err_unlock:
+ spin_unlock_irqrestore(&dev->event_lock, flags);
+ kfree(e);
+err_put:
+ drm_vblank_put(dev, pipe);
+ return ret;
+}
+
+/*
+ * Wait for VBLANK.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param data user argument, pointing to a drm_wait_vblank structure.
+ * \return zero on success or a negative number on failure.
+ *
+ * This function enables the vblank interrupt on the pipe requested, then
+ * sleeps waiting for the requested sequence number to occur, and drops
+ * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
+ * after a timeout with no further vblank waits scheduled).
+ */
+int drm_wait_vblank(struct drm_device *dev, void *data,
+ struct drm_file *file_priv)
+{
+ struct drm_vblank_crtc *vblank;
+ union drm_wait_vblank *vblwait = data;
+ int ret;
+ unsigned int flags, seq, crtc, high_crtc;
+
+ if (!dev->irq_enabled)
+ return -EINVAL;
+
+ if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
+ return -EINVAL;
+
+ if (vblwait->request.type &
+ ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+ _DRM_VBLANK_HIGH_CRTC_MASK)) {
+ DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
+ vblwait->request.type,
+ (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
+ _DRM_VBLANK_HIGH_CRTC_MASK));
+ return -EINVAL;
+ }
+
+ flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
+ high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
+ if (high_crtc)
+ crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
+ else
+ crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
+ if (crtc >= dev->num_crtcs)
+ return -EINVAL;
+
+ vblank = &dev->vblank[crtc];
+
+ ret = drm_vblank_get(dev, crtc);
+ if (ret) {
+ DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
+ return ret;
+ }
+ seq = drm_vblank_count(dev, crtc);
+
+ switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
+ case _DRM_VBLANK_RELATIVE:
+ vblwait->request.sequence += seq;
+ vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
+ case _DRM_VBLANK_ABSOLUTE:
+ break;
+ default:
+ ret = -EINVAL;
+ goto done;
+ }
+
+ if (flags & _DRM_VBLANK_EVENT) {
+ /* must hold on to the vblank ref until the event fires
+ * drm_vblank_put will be called asynchronously
+ */
+ return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
+ }
+
+ if ((flags & _DRM_VBLANK_NEXTONMISS) &&
+ (seq - vblwait->request.sequence) <= (1<<23)) {
+ vblwait->request.sequence = seq + 1;
+ }
+
+ DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
+ vblwait->request.sequence, crtc);
+ vblank->last_wait = vblwait->request.sequence;
+ DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
+ (((drm_vblank_count(dev, crtc) -
+ vblwait->request.sequence) <= (1 << 23)) ||
+ !vblank->enabled ||
+ !dev->irq_enabled));
+
+ if (ret != -EINTR) {
+ struct timeval now;
+
+ vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
+ vblwait->reply.tval_sec = now.tv_sec;
+ vblwait->reply.tval_usec = now.tv_usec;
+
+ DRM_DEBUG("returning %d to client\n",
+ vblwait->reply.sequence);
+ } else {
+ DRM_DEBUG("vblank wait interrupted by signal\n");
+ }
+
+done:
+ drm_vblank_put(dev, crtc);
+ return ret;
+}
+
+static void drm_handle_vblank_events(struct drm_device *dev, int crtc)
+{
+ struct drm_pending_vblank_event *e, *t;
+ struct timeval now;
+ unsigned int seq;
+
+ assert_spin_locked(&dev->event_lock);
+
+ seq = drm_vblank_count_and_time(dev, crtc, &now);
+
+ list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
+ if (e->pipe != crtc)
+ continue;
+ if ((seq - e->event.sequence) > (1<<23))
+ continue;
+
+ DRM_DEBUG("vblank event on %d, current %d\n",
+ e->event.sequence, seq);
+
+ list_del(&e->base.link);
+ drm_vblank_put(dev, e->pipe);
+ send_vblank_event(dev, e, seq, &now);
+ }
+
+ trace_drm_vblank_event(crtc, seq);
+}
+
+/**
+ * drm_handle_vblank - handle a vblank event
+ * @dev: DRM device
+ * @crtc: where this event occurred
+ *
+ * Drivers should call this routine in their vblank interrupt handlers to
+ * update the vblank counter and send any signals that may be pending.
+ *
+ * This is the legacy version of drm_crtc_handle_vblank().
+ */
+bool drm_handle_vblank(struct drm_device *dev, int crtc)
+{
+ struct drm_vblank_crtc *vblank = &dev->vblank[crtc];
+ u32 vblcount;
+ s64 diff_ns;
+ struct timeval tvblank;
+ unsigned long irqflags;
+
+ if (WARN_ON_ONCE(!dev->num_crtcs))
+ return false;
+
+ if (WARN_ON(crtc >= dev->num_crtcs))
+ return false;
+
+ spin_lock_irqsave(&dev->event_lock, irqflags);
+
+ /* Need timestamp lock to prevent concurrent execution with
+ * vblank enable/disable, as this would cause inconsistent
+ * or corrupted timestamps and vblank counts.
+ */
+ spin_lock(&dev->vblank_time_lock);
+
+ /* Vblank irq handling disabled. Nothing to do. */
+ if (!vblank->enabled) {
+ spin_unlock(&dev->vblank_time_lock);
+ spin_unlock_irqrestore(&dev->event_lock, irqflags);
+ return false;
+ }
+
+ /* Fetch corresponding timestamp for this vblank interval from
+ * driver and store it in proper slot of timestamp ringbuffer.
+ */
+
+ /* Get current timestamp and count. */
+ vblcount = atomic_read(&vblank->count);
+ drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
+
+ /* Compute time difference to timestamp of last vblank */
+ diff_ns = timeval_to_ns(&tvblank) -
+ timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
+
+ /* Update vblank timestamp and count if at least
+ * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
+ * difference between last stored timestamp and current
+ * timestamp. A smaller difference means basically
+ * identical timestamps. Happens if this vblank has
+ * been already processed and this is a redundant call,
+ * e.g., due to spurious vblank interrupts. We need to
+ * ignore those for accounting.
+ */
+ if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
+ /* Store new timestamp in ringbuffer. */
+ vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
+
+ /* Increment cooked vblank count. This also atomically commits
+ * the timestamp computed above.
+ */
+ smp_mb__before_atomic();
+ atomic_inc(&vblank->count);
+ smp_mb__after_atomic();
+ } else {
+ DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
+ crtc, (int) diff_ns);
+ }
+
+ spin_unlock(&dev->vblank_time_lock);
+
+ wake_up(&vblank->queue);
+ drm_handle_vblank_events(dev, crtc);
+
+ spin_unlock_irqrestore(&dev->event_lock, irqflags);
+
+ return true;
+}
+EXPORT_SYMBOL(drm_handle_vblank);
+
+/**
+ * drm_crtc_handle_vblank - handle a vblank event
+ * @crtc: where this event occurred
+ *
+ * Drivers should call this routine in their vblank interrupt handlers to
+ * update the vblank counter and send any signals that may be pending.
+ *
+ * This is the native KMS version of drm_handle_vblank().
+ *
+ * Returns:
+ * True if the event was successfully handled, false on failure.
+ */
+bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
+{
+ return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
+}
+EXPORT_SYMBOL(drm_crtc_handle_vblank);
Code Review / kvmfornfv.git / blobdiff