From: Michel Dänzer michel.daenzer@amd.com
This prevents a panic: radeon_crtc_handle_page_flip() could run before radeon_flip_work_func(), triggering the BUG_ON() in drm_vblank_put().
Tested-by: Dieter Nützel Dieter@nuetzel-hh.de Signed-off-by: Michel Dänzer michel.daenzer@amd.com ---
v2: Update log message
drivers/gpu/drm/radeon/radeon_display.c | 19 ++++++++++++++----- drivers/gpu/drm/radeon/radeon_mode.h | 7 +++++++ 2 files changed, 21 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c index 8b575a4..65882cd 100644 --- a/drivers/gpu/drm/radeon/radeon_display.c +++ b/drivers/gpu/drm/radeon/radeon_display.c @@ -284,7 +284,6 @@ static void radeon_unpin_work_func(struct work_struct *__work) void radeon_crtc_handle_vblank(struct radeon_device *rdev, int crtc_id) { struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[crtc_id]; - struct radeon_flip_work *work; unsigned long flags; u32 update_pending; int vpos, hpos; @@ -294,8 +293,11 @@ void radeon_crtc_handle_vblank(struct radeon_device *rdev, int crtc_id) return;
spin_lock_irqsave(&rdev->ddev->event_lock, flags); - work = radeon_crtc->flip_work; - if (work == NULL) { + if (radeon_crtc->flip_status != RADEON_FLIP_SUBMITTED) { + DRM_DEBUG_DRIVER("radeon_crtc->flip_status = %d != " + "RADEON_FLIP_SUBMITTED(%d)\n", + radeon_crtc->flip_status, + RADEON_FLIP_SUBMITTED); spin_unlock_irqrestore(&rdev->ddev->event_lock, flags); return; } @@ -343,12 +345,17 @@ void radeon_crtc_handle_flip(struct radeon_device *rdev, int crtc_id)
spin_lock_irqsave(&rdev->ddev->event_lock, flags); work = radeon_crtc->flip_work; - if (work == NULL) { + if (radeon_crtc->flip_status != RADEON_FLIP_SUBMITTED) { + DRM_DEBUG_DRIVER("radeon_crtc->flip_status = %d != " + "RADEON_FLIP_SUBMITTED(%d)\n", + radeon_crtc->flip_status, + RADEON_FLIP_SUBMITTED); spin_unlock_irqrestore(&rdev->ddev->event_lock, flags); return; }
/* Pageflip completed. Clean up. */ + radeon_crtc->flip_status = RADEON_FLIP_NONE; radeon_crtc->flip_work = NULL;
/* wakeup userspace */ @@ -475,6 +482,7 @@ static void radeon_flip_work_func(struct work_struct *__work) /* do the flip (mmio) */ radeon_page_flip(rdev, radeon_crtc->crtc_id, base);
+ radeon_crtc->flip_status = RADEON_FLIP_SUBMITTED; spin_unlock_irqrestore(&crtc->dev->event_lock, flags); up_read(&rdev->exclusive_lock);
@@ -543,7 +551,7 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc, /* We borrow the event spin lock for protecting flip_work */ spin_lock_irqsave(&crtc->dev->event_lock, flags);
- if (radeon_crtc->flip_work) { + if (radeon_crtc->flip_status != RADEON_FLIP_NONE) { DRM_DEBUG_DRIVER("flip queue: crtc already busy\n"); spin_unlock_irqrestore(&crtc->dev->event_lock, flags); drm_gem_object_unreference_unlocked(&work->old_rbo->gem_base); @@ -551,6 +559,7 @@ static int radeon_crtc_page_flip(struct drm_crtc *crtc, kfree(work); return -EBUSY; } + radeon_crtc->flip_status = RADEON_FLIP_PENDING; radeon_crtc->flip_work = work;
/* update crtc fb */ diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h index b59096f..ed6b6e0 100644 --- a/drivers/gpu/drm/radeon/radeon_mode.h +++ b/drivers/gpu/drm/radeon/radeon_mode.h @@ -301,6 +301,12 @@ struct radeon_atom_ss { uint16_t amount; };
+enum radeon_flip_status { + RADEON_FLIP_NONE, + RADEON_FLIP_PENDING, + RADEON_FLIP_SUBMITTED +}; + struct radeon_crtc { struct drm_crtc base; int crtc_id; @@ -326,6 +332,7 @@ struct radeon_crtc { /* page flipping */ struct workqueue_struct *flip_queue; struct radeon_flip_work *flip_work; + enum radeon_flip_status flip_status; /* pll sharing */ struct radeon_atom_ss ss; bool ss_enabled;