We can't rely on crtc->primary->fb in the page flip worker, as a racing CRTC disable (due for instance to an explicit framebuffer deletion from userspace) would set that field to NULL before the worker gets a change to run. Store the framebuffer queued for page flip in a new field of omap_crtc instead, and hold a reference to it.
Signed-off-by: Laurent Pinchart laurent.pinchart@ideasonboard.com --- drivers/gpu/drm/omapdrm/omap_crtc.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c index 1076bc0..68abc4d 100644 --- a/drivers/gpu/drm/omapdrm/omap_crtc.c +++ b/drivers/gpu/drm/omapdrm/omap_crtc.c @@ -66,7 +66,8 @@ struct omap_crtc { * page queue has been submitted, WAIT when waiting for GEM async * completion, QUEUED when the page flip has been queued to the hardware * or CANCELLED when the CRTC is turned off before the flip gets queued - * to the hardware. The flip event, if any, is stored in flip_event. The + * to the hardware. The flip event, if any, is stored in flip_event, and + * the framebuffer queued for page flip is stored in flip_fb. The * flip_wait wait queue is used to wait for page flip completion. * * The flip_work work queue handles page flip requests without caring @@ -76,6 +77,7 @@ struct omap_crtc { */ enum omap_page_flip_state flip_state; struct drm_pending_vblank_event *flip_event; + struct drm_framebuffer *flip_fb; wait_queue_head_t flip_wait; struct work_struct flip_work;
@@ -630,6 +632,7 @@ static void page_flip_worker(struct work_struct *work) drm_modeset_lock(&crtc->mutex, NULL);
spin_lock_irqsave(&dev->event_lock, flags); + /* * The page flip could have been cancelled while waiting for the GEM * async operation to complete. Don't queue the flip in that case. @@ -641,9 +644,11 @@ static void page_flip_worker(struct work_struct *work) omap_crtc->flip_state = OMAP_PAGE_FLIP_IDLE; queue_flip = false; } - spin_unlock_irqrestore(&dev->event_lock, flags);
- fb = crtc->primary->fb; + fb = omap_crtc->flip_fb; + omap_crtc->flip_fb = NULL; + + spin_unlock_irqrestore(&dev->event_lock, flags);
if (queue_flip) { omap_plane_mode_set(crtc->primary, crtc, fb, @@ -657,7 +662,7 @@ static void page_flip_worker(struct work_struct *work)
bo = omap_framebuffer_bo(fb, 0); drm_gem_object_unreference_unlocked(bo); - drm_framebuffer_unreference(crtc->primary->fb); + drm_framebuffer_unreference(fb); }
static void page_flip_cb(void *arg) @@ -692,10 +697,19 @@ static int omap_crtc_page_flip(struct drm_crtc *crtc, return -EBUSY; }
+ /* + * Store a reference to the framebuffer queued for page flip in the CRTC + * private structure. We can't rely on crtc->primary->fb in the page + * flip worker, as a racing CRTC disable (due for instance to an + * explicit framebuffer deletion from userspace) would set that field to + * NULL before the worker gets a change to run. + */ + drm_framebuffer_reference(fb); + omap_crtc->flip_fb = fb; omap_crtc->flip_event = event; omap_crtc->flip_state = OMAP_PAGE_FLIP_WAIT; + primary->fb = fb; - drm_framebuffer_reference(fb);
spin_unlock_irqrestore(&dev->event_lock, flags);