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@xxxxxxxxxxxxxxxx>
---
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);
--
2.0.5
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