Instead of taking fbc->lock inside the worker, don't take any lock and cancel the work synchronously to prevent races. Since the worker waits for a vblank before activating, wake up all vblank waiters after signalling the cancel through unsetting work->scheduled_vblank. This will make sure that we don't wait too long when cancelling the activation.
Signed-off-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com> Cc: Paulo Zanoni <paulo.r.zan...@intel.com> Cc: Rodrigo Vivi <rodrigo.v...@intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103167 --- drivers/gpu/drm/i915/i915_debugfs.c | 4 +- drivers/gpu/drm/i915/i915_drv.h | 3 +- drivers/gpu/drm/i915/intel_fbc.c | 76 ++++++++++++++++--------------------- 3 files changed, 36 insertions(+), 47 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 98e169636f86..cbf5504de183 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -1643,9 +1643,9 @@ static int i915_fbc_status(struct seq_file *m, void *unused) else seq_printf(m, "FBC disabled: %s\n", fbc->no_fbc_reason); - if (fbc->work.scheduled) + if (work_busy(&fbc->work.work)) seq_printf(m, "FBC worker scheduled on vblank %llu, now %llu\n", - fbc->work.scheduled_vblank, + (u64)atomic64_read(&fbc->work.scheduled_vblank), drm_crtc_vblank_count(&fbc->crtc->base)); if (intel_fbc_is_active(dev_priv)) { diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 9262cfb8aac2..a7a1b0453320 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -558,8 +558,7 @@ struct intel_fbc { } params; struct intel_fbc_work { - bool scheduled; - u64 scheduled_vblank; + atomic64_t scheduled_vblank; struct work_struct work; } work; diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c index 707d49c12638..20d45bcb6b6b 100644 --- a/drivers/gpu/drm/i915/intel_fbc.c +++ b/drivers/gpu/drm/i915/intel_fbc.c @@ -357,10 +357,6 @@ static bool intel_fbc_hw_is_active(struct drm_i915_private *dev_priv) static void intel_fbc_hw_activate(struct drm_i915_private *dev_priv) { - struct intel_fbc *fbc = &dev_priv->fbc; - - fbc->active = true; - if (INTEL_GEN(dev_priv) >= 7) gen7_fbc_activate(dev_priv); else if (INTEL_GEN(dev_priv) >= 5) @@ -407,16 +403,13 @@ static void intel_fbc_work_fn(struct work_struct *__work) struct intel_fbc_work *work = &fbc->work; struct intel_crtc *crtc = fbc->crtc; struct drm_vblank_crtc *vblank = &dev_priv->drm.vblank[crtc->pipe]; + u64 vbl; if (drm_crtc_vblank_get(&crtc->base)) { /* CRTC is now off, leave FBC deactivated */ - mutex_lock(&fbc->lock); - work->scheduled = false; - mutex_unlock(&fbc->lock); return; } -retry: /* Delay the actual enabling to let pageflipping cease and the * display to settle before starting the compression. Note that * this delay also serves a second purpose: it allows for a @@ -425,34 +418,35 @@ static void intel_fbc_work_fn(struct work_struct *__work) * * WaFbcWaitForVBlankBeforeEnable:ilk,snb * - * It is also worth mentioning that since work->scheduled_vblank can be - * updated multiple times by the other threads, hitting the timeout is - * not an error condition. We'll just end up hitting the "goto retry" - * case below. + * This may be killed by unsetting scheduled_vblank, in which + * case we return early without activating. */ wait_event_timeout(vblank->queue, - drm_crtc_vblank_count(&crtc->base) != work->scheduled_vblank, + !(vbl = atomic64_read(&work->scheduled_vblank)) || vbl != drm_crtc_vblank_count(&crtc->base), msecs_to_jiffies(50)); - mutex_lock(&fbc->lock); + if (vbl) + intel_fbc_hw_activate(dev_priv); - /* Were we cancelled? */ - if (!work->scheduled) - goto out; + drm_crtc_vblank_put(&crtc->base); +} - /* Were we delayed again while this function was sleeping? */ - if (drm_crtc_vblank_count(&crtc->base) == work->scheduled_vblank) { - mutex_unlock(&fbc->lock); - goto retry; - } +static void intel_fbc_cancel_activation(struct drm_i915_private *dev_priv) +{ + struct intel_fbc *fbc = &dev_priv->fbc; + struct intel_crtc *crtc; + struct drm_vblank_crtc *vblank; - intel_fbc_hw_activate(dev_priv); + if (!fbc->active) + return; - work->scheduled = false; + crtc = fbc->crtc; + vblank = &dev_priv->drm.vblank[crtc->pipe]; -out: - mutex_unlock(&fbc->lock); - drm_crtc_vblank_put(&crtc->base); + /* Kill FBC worker if it's waiting */ + atomic64_set(&fbc->work.scheduled_vblank, 0); + wake_up_all(&vblank->queue); + cancel_work_sync(&fbc->work.work); } static void intel_fbc_schedule_activation(struct intel_crtc *crtc) @@ -471,12 +465,10 @@ static void intel_fbc_schedule_activation(struct intel_crtc *crtc) return; } - /* It is useless to call intel_fbc_cancel_work() or cancel_work() in - * this function since we're not releasing fbc.lock, so it won't have an - * opportunity to grab it to discover that it was cancelled. So we just - * update the expected jiffy count. */ - work->scheduled = true; - work->scheduled_vblank = drm_crtc_vblank_count(&crtc->base); + intel_fbc_cancel_activation(dev_priv); + fbc->active = true; + + atomic64_set(&work->scheduled_vblank, drm_crtc_accurate_vblank_count(&crtc->base)); drm_crtc_vblank_put(&crtc->base); schedule_work(&work->work); @@ -489,13 +481,11 @@ static void intel_fbc_deactivate(struct drm_i915_private *dev_priv, WARN_ON(!mutex_is_locked(&fbc->lock)); - /* Calling cancel_work() here won't help due to the fact that the work - * function grabs fbc->lock. Just set scheduled to false so the work - * function can know it was cancelled. */ - fbc->work.scheduled = false; + if (fbc->active) { + intel_fbc_cancel_activation(dev_priv); - if (fbc->active) intel_fbc_hw_deactivate(dev_priv); + } fbc->no_fbc_reason = reason; } @@ -1222,11 +1212,11 @@ void intel_fbc_disable(struct intel_crtc *crtc) WARN_ON(crtc->active); mutex_lock(&fbc->lock); + intel_fbc_cancel_activation(dev_priv); + if (fbc->crtc == crtc) __intel_fbc_disable(dev_priv); mutex_unlock(&fbc->lock); - - cancel_work_sync(&fbc->work.work); } /** @@ -1243,13 +1233,13 @@ void intel_fbc_global_disable(struct drm_i915_private *dev_priv) return; mutex_lock(&fbc->lock); + intel_fbc_cancel_activation(dev_priv); + if (fbc->enabled) { WARN_ON(fbc->crtc->active); __intel_fbc_disable(dev_priv); } mutex_unlock(&fbc->lock); - - cancel_work_sync(&fbc->work.work); } static void intel_fbc_underrun_work_fn(struct work_struct *work) @@ -1373,11 +1363,11 @@ void intel_fbc_init(struct drm_i915_private *dev_priv) struct intel_fbc *fbc = &dev_priv->fbc; INIT_WORK(&fbc->work.work, intel_fbc_work_fn); + atomic64_set(&fbc->work.scheduled_vblank, 0); INIT_WORK(&fbc->underrun_work, intel_fbc_underrun_work_fn); mutex_init(&fbc->lock); fbc->enabled = false; fbc->active = false; - fbc->work.scheduled = false; if (need_fbc_vtd_wa(dev_priv)) mkwrite_device_info(dev_priv)->has_fbc = false; -- 2.16.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
