| /** |
| * \file drm_irq.c |
| * IRQ 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 <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 |
| |
| /* |
| * Clear vblank timestamp buffer for a crtc. |
| */ |
| static void clear_vblank_timestamps(struct drm_device *dev, int crtc) |
| { |
| memset(dev->vblank[crtc].time, 0, sizeof(dev->vblank[crtc].time)); |
| } |
| |
| /* |
| * 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) |
| { |
| unsigned long irqflags; |
| u32 vblcount; |
| s64 diff_ns; |
| int 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); |
| |
| dev->driver->disable_vblank(dev, crtc); |
| dev->vblank[crtc].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 { |
| dev->vblank[crtc].last = dev->driver->get_vblank_counter(dev, crtc); |
| vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0); |
| } while (dev->vblank[crtc].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(&dev->vblank[crtc].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 > 0) && (abs64(diff_ns) > 1000000)) { |
| atomic_inc(&dev->vblank[crtc].count); |
| smp_mb__after_atomic_inc(); |
| } |
| |
| /* Invalidate all timestamps while vblank irq's are off. */ |
| clear_vblank_timestamps(dev, crtc); |
| |
| spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); |
| } |
| |
| static void vblank_disable_fn(unsigned long arg) |
| { |
| struct drm_device *dev = (struct drm_device *)arg; |
| unsigned long irqflags; |
| int i; |
| |
| if (!dev->vblank_disable_allowed) |
| return; |
| |
| for (i = 0; i < dev->num_crtcs; i++) { |
| spin_lock_irqsave(&dev->vbl_lock, irqflags); |
| if (atomic_read(&dev->vblank[i].refcount) == 0 && |
| dev->vblank[i].enabled) { |
| DRM_DEBUG("disabling vblank on crtc %d\n", i); |
| vblank_disable_and_save(dev, i); |
| } |
| spin_unlock_irqrestore(&dev->vbl_lock, irqflags); |
| } |
| } |
| |
| void drm_vblank_cleanup(struct drm_device *dev) |
| { |
| /* Bail if the driver didn't call drm_vblank_init() */ |
| if (dev->num_crtcs == 0) |
| return; |
| |
| del_timer_sync(&dev->vblank_disable_timer); |
| |
| vblank_disable_fn((unsigned long)dev); |
| |
| kfree(dev->vblank); |
| |
| dev->num_crtcs = 0; |
| } |
| EXPORT_SYMBOL(drm_vblank_cleanup); |
| |
| int drm_vblank_init(struct drm_device *dev, int num_crtcs) |
| { |
| int i, ret = -ENOMEM; |
| |
| setup_timer(&dev->vblank_disable_timer, vblank_disable_fn, |
| (unsigned long)dev); |
| 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++) |
| init_waitqueue_head(&dev->vblank[i].queue); |
| |
| 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: |
| drm_vblank_cleanup(dev); |
| 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); |
| } |
| } |
| |
| /** |
| * Install IRQ handler. |
| * |
| * \param dev DRM device. |
| * |
| * Initializes the IRQ related data. Installs the handler, calling the driver |
| * \c irq_preinstall() and \c irq_postinstall() functions |
| * before and after the installation. |
| */ |
| 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); |
| |
| /** |
| * Uninstall the IRQ handler. |
| * |
| * \param dev DRM device. |
| * |
| * Calls the driver's \c irq_uninstall() function, and stops the irq. |
| */ |
| 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. |
| */ |
| if (dev->num_crtcs) { |
| spin_lock_irqsave(&dev->vbl_lock, irqflags); |
| for (i = 0; i < dev->num_crtcs; i++) { |
| wake_up(&dev->vblank[i].queue); |
| dev->vblank[i].enabled = false; |
| dev->vblank[i].last = |
| dev->driver->get_vblank_counter(dev, i); |
| } |
| 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 - helper routine for kms |
| * drivers. 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. |
| * |
| * @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: drm_crtc* of crtc which defines scanout timing. |
| * @mode: mode which defines the scanout timings |
| * |
| * 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) |
| { |
| ktime_t stime, etime, mono_time_offset; |
| struct timeval tv_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); |
| |
| /* |
| * Get correction for CLOCK_MONOTONIC -> CLOCK_REALTIME if |
| * CLOCK_REALTIME is requested. |
| */ |
| if (!drm_timestamp_monotonic) |
| mono_time_offset = ktime_get_monotonic_offset(); |
| |
| /* 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_INVBL; |
| |
| /* 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_sub(etime, mono_time_offset); |
| |
| /* 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_INVBL; |
| |
| return vbl_status; |
| } |
| EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos); |
| |
| static struct timeval get_drm_timestamp(void) |
| { |
| ktime_t now; |
| |
| now = ktime_get(); |
| if (!drm_timestamp_monotonic) |
| now = ktime_sub(now, ktime_get_monotonic_offset()); |
| |
| 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 non-zero if timestamp is considered to be very precise. |
| */ |
| u32 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 (u32) ret; |
| } |
| |
| /* GPU high precision timestamp query unsupported or failed. |
| * Return current monotonic/gettimeofday timestamp as best estimate. |
| */ |
| *tvblank = get_drm_timestamp(); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(drm_get_last_vbltimestamp); |
| |
| /** |
| * 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. |
| */ |
| u32 drm_vblank_count(struct drm_device *dev, int crtc) |
| { |
| return atomic_read(&dev->vblank[crtc].count); |
| } |
| EXPORT_SYMBOL(drm_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 value vblank counter |
| * value. |
| */ |
| u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, |
| struct timeval *vblanktime) |
| { |
| u32 cur_vblank; |
| |
| /* 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(&dev->vblank[crtc].count); |
| *vblanktime = vblanktimestamp(dev, crtc, cur_vblank); |
| smp_rmb(); |
| } while (cur_vblank != atomic_read(&dev->vblank[crtc].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. |
| */ |
| 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_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) |
| { |
| u32 cur_vblank, diff, tslot, 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 - dev->vblank[crtc].last; |
| if (cur_vblank < dev->vblank[crtc].last) { |
| diff += dev->max_vblank_count; |
| |
| DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n", |
| crtc, dev->vblank[crtc].last, cur_vblank, diff); |
| } |
| |
| DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n", |
| crtc, diff); |
| |
| /* 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. |
| */ |
| if (rc) { |
| tslot = atomic_read(&dev->vblank[crtc].count) + diff; |
| vblanktimestamp(dev, crtc, tslot) = t_vblank; |
| } |
| |
| smp_mb__before_atomic_inc(); |
| atomic_add(diff, &dev->vblank[crtc].count); |
| smp_mb__after_atomic_inc(); |
| } |
| |
| /** |
| * 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. |
| * |
| * RETURNS |
| * Zero on success, nonzero on failure. |
| */ |
| int drm_vblank_get(struct drm_device *dev, int crtc) |
| { |
| unsigned long irqflags; |
| int ret = 0; |
| |
| spin_lock_irqsave(&dev->vbl_lock, irqflags); |
| /* Going from 0->1 means we have to enable interrupts again */ |
| if (atomic_add_return(1, &dev->vblank[crtc].refcount) == 1) { |
| spin_lock(&dev->vblank_time_lock); |
| if (!dev->vblank[crtc].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(&dev->vblank[crtc].refcount); |
| else { |
| dev->vblank[crtc].enabled = true; |
| drm_update_vblank_count(dev, crtc); |
| } |
| } |
| spin_unlock(&dev->vblank_time_lock); |
| } else { |
| if (!dev->vblank[crtc].enabled) { |
| atomic_dec(&dev->vblank[crtc].refcount); |
| ret = -EINVAL; |
| } |
| } |
| spin_unlock_irqrestore(&dev->vbl_lock, irqflags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(drm_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. |
| */ |
| void drm_vblank_put(struct drm_device *dev, int crtc) |
| { |
| BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0); |
| |
| /* Last user schedules interrupt disable */ |
| if (atomic_dec_and_test(&dev->vblank[crtc].refcount) && |
| (drm_vblank_offdelay > 0)) |
| mod_timer(&dev->vblank_disable_timer, |
| jiffies + ((drm_vblank_offdelay * HZ)/1000)); |
| } |
| EXPORT_SYMBOL(drm_vblank_put); |
| |
| /** |
| * drm_vblank_off - disable vblank events on a CRTC |
| * @dev: DRM device |
| * @crtc: CRTC in question |
| * |
| * Caller must hold event lock. |
| */ |
| void drm_vblank_off(struct drm_device *dev, int crtc) |
| { |
| struct drm_pending_vblank_event *e, *t; |
| struct timeval now; |
| unsigned long irqflags; |
| unsigned int seq; |
| |
| spin_lock_irqsave(&dev->vbl_lock, irqflags); |
| vblank_disable_and_save(dev, crtc); |
| wake_up(&dev->vblank[crtc].queue); |
| |
| /* Send any queued vblank events, lest the natives grow disquiet */ |
| seq = drm_vblank_count_and_time(dev, crtc, &now); |
| |
| spin_lock(&dev->event_lock); |
| 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(&dev->event_lock); |
| |
| spin_unlock_irqrestore(&dev->vbl_lock, irqflags); |
| } |
| EXPORT_SYMBOL(drm_vblank_off); |
| |
| /** |
| * 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. |
| */ |
| void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) |
| { |
| /* vblank is not initialized (IRQ not installed ?), or has been freed */ |
| if (!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 (!dev->vblank[crtc].inmodeset) { |
| dev->vblank[crtc].inmodeset = 0x1; |
| if (drm_vblank_get(dev, crtc) == 0) |
| dev->vblank[crtc].inmodeset |= 0x2; |
| } |
| } |
| EXPORT_SYMBOL(drm_vblank_pre_modeset); |
| |
| void drm_vblank_post_modeset(struct drm_device *dev, int crtc) |
| { |
| unsigned long irqflags; |
| |
| /* vblank is not initialized (IRQ not installed ?), or has been freed */ |
| if (!dev->num_crtcs) |
| return; |
| |
| if (dev->vblank[crtc].inmodeset) { |
| spin_lock_irqsave(&dev->vbl_lock, irqflags); |
| dev->vblank_disable_allowed = true; |
| spin_unlock_irqrestore(&dev->vbl_lock, irqflags); |
| |
| if (dev->vblank[crtc].inmodeset & 0x2) |
| drm_vblank_put(dev, crtc); |
| |
| dev->vblank[crtc].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_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); |
| |
| 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) |
| { |
| 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; |
| |
| 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); |
| dev->vblank[crtc].last_wait = vblwait->request.sequence; |
| DRM_WAIT_ON(ret, dev->vblank[crtc].queue, 3 * HZ, |
| (((drm_vblank_count(dev, crtc) - |
| vblwait->request.sequence) <= (1 << 23)) || |
| !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 long flags; |
| unsigned int seq; |
| |
| seq = drm_vblank_count_and_time(dev, crtc, &now); |
| |
| spin_lock_irqsave(&dev->event_lock, flags); |
| |
| 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); |
| } |
| |
| spin_unlock_irqrestore(&dev->event_lock, flags); |
| |
| 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. |
| */ |
| bool drm_handle_vblank(struct drm_device *dev, int crtc) |
| { |
| u32 vblcount; |
| s64 diff_ns; |
| struct timeval tvblank; |
| unsigned long irqflags; |
| |
| if (!dev->num_crtcs) |
| return false; |
| |
| /* Need timestamp lock to prevent concurrent execution with |
| * vblank enable/disable, as this would cause inconsistent |
| * or corrupted timestamps and vblank counts. |
| */ |
| spin_lock_irqsave(&dev->vblank_time_lock, irqflags); |
| |
| /* Vblank irq handling disabled. Nothing to do. */ |
| if (!dev->vblank[crtc].enabled) { |
| spin_unlock_irqrestore(&dev->vblank_time_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(&dev->vblank[crtc].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_inc(); |
| atomic_inc(&dev->vblank[crtc].count); |
| smp_mb__after_atomic_inc(); |
| } else { |
| DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", |
| crtc, (int) diff_ns); |
| } |
| |
| wake_up(&dev->vblank[crtc].queue); |
| drm_handle_vblank_events(dev, crtc); |
| |
| spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); |
| return true; |
| } |
| EXPORT_SYMBOL(drm_handle_vblank); |