From e6ae8687a87b1fe5c25e824c8ad300f5587eb622 Mon Sep 17 00:00:00 2001 From: Rob Clark Date: Wed, 6 Aug 2014 13:16:59 -0400 Subject: drm: idiot-proof vblank After spending slightly more time than I'd care to admit debugging the various and presumably spectacular way things fail when you pass too low a value to drm_vblank_init() (thanks console-lock for not letting me see the carnage!), I decided it might be a good idea to add some sanity checking. Signed-off-by: Rob Clark Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_irq.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'drivers/gpu/drm/drm_irq.c') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 0de123a..6f16a10 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -730,6 +730,8 @@ EXPORT_SYMBOL(drm_get_last_vbltimestamp); */ u32 drm_vblank_count(struct drm_device *dev, int crtc) { + if (WARN_ON(crtc >= dev->num_crtcs)) + return 0; return atomic_read(&dev->vblank[crtc].count); } EXPORT_SYMBOL(drm_vblank_count); @@ -752,6 +754,9 @@ u32 drm_vblank_count_and_time(struct drm_device *dev, int 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 @@ -927,6 +932,9 @@ int drm_vblank_get(struct drm_device *dev, int 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, &dev->vblank[crtc].refcount) == 1) { @@ -975,6 +983,9 @@ void drm_vblank_put(struct drm_device *dev, int crtc) { BUG_ON(atomic_read(&dev->vblank[crtc].refcount) == 0); + if (WARN_ON(crtc >= dev->num_crtcs)) + return; + /* Last user schedules interrupt disable */ if (atomic_dec_and_test(&dev->vblank[crtc].refcount) && (drm_vblank_offdelay > 0)) @@ -1019,6 +1030,9 @@ void drm_vblank_off(struct drm_device *dev, int crtc) unsigned long irqflags; unsigned int seq; + if (WARN_ON(crtc >= dev->num_crtcs)) + return; + spin_lock_irqsave(&dev->vbl_lock, irqflags); vblank_disable_and_save(dev, crtc); wake_up(&dev->vblank[crtc].queue); @@ -1078,6 +1092,9 @@ void drm_vblank_on(struct drm_device *dev, int crtc) { unsigned long irqflags; + if (WARN_ON(crtc >= dev->num_crtcs)) + return; + spin_lock_irqsave(&dev->vbl_lock, irqflags); /* re-enable interrupts if there's are users left */ if (atomic_read(&dev->vblank[crtc].refcount) != 0) @@ -1131,6 +1148,10 @@ 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; + + 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 @@ -1439,6 +1460,9 @@ bool drm_handle_vblank(struct drm_device *dev, int crtc) if (!dev->num_crtcs) return false; + if (WARN_ON(crtc >= 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. -- cgit v1.1 From e8450f51a4b39cfe0878b4aee339820b2bfff240 Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Fri, 25 Jul 2014 23:34:03 +0200 Subject: drm/irq: Implement a generic vblank_wait function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As usual in both a crtc index and a struct drm_crtc * version. The function assumes that no one drivers their display below 10Hz, and it will complain if the vblank wait takes longer than that. v2: Also check dev->max_vblank_counter since some drivers register a fake get_vblank_counter function. v3: Use drm_vblank_count instead of calling the low-level ->get_vblank_counter callback. That way we'll get the sw-cooked counter for platforms without proper vblank support and so can ditch the max_vblank_counter check again. v4: Review from Michel Dänzer: - Restore lost notes about v3: - Spelling in kerneldoc. - Inline wait_event condition. - s/vblank_wait/wait_one_vblank/ Cc: Michel Dänzer Cc: Ville Syrjälä Reviewed-by: Michel Dänzer Reviewed-by: Matt Roper Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_irq.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'drivers/gpu/drm/drm_irq.c') diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 6f16a10..e64d249 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1010,6 +1010,50 @@ void drm_crtc_vblank_put(struct drm_crtc *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_ON(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_ON(ret == 0); + + 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 -- cgit v1.1