@@ -455,7 +455,7 @@ static void radeon_flip_work_func(struct work_struct *__work)
* In practice this won't execute very often unless on very fast
* machines because the time window for this to happen is very small.
*/
- while (radeon_crtc->enabled && repcnt--) {
+ while (radeon_crtc->enabled && --repcnt) {
/* GET_DISTANCE_TO_VBLANKSTART returns distance to real vblank
* start in hpos, and to the "fudged earlier" vblank start in
* vpos.
@@ -471,13 +471,13 @@ static void radeon_flip_work_func(struct work_struct *__work)
break;
/* Sleep at least until estimated real start of hw vblank */
- spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
min_udelay = (-hpos + 1) * max(vblank->linedur_ns / 1000, 5);
if (min_udelay > vblank->framedur_ns / 2000) {
/* Don't wait ridiculously long - something is wrong */
repcnt = 0;
break;
}
+ spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
usleep_range(min_udelay, 2 * min_udelay);
spin_lock_irqsave(&crtc->dev->event_lock, flags);
};
This is a port of the patch "drm/amdgpu: Fix error handling in amdgpu_flip_work_func." to fix the following problem for radeon as well which was reported against amdgpu: The patch e1d09dc0ccc6: "drm/amdgpu: Don't hang in amdgpu_flip_work_func on disabled crtc." from Feb 19, 2016, leads to the following static checker warning, as reported by Dan Carpenter in https://lists.freedesktop.org/archives/dri-devel/2016-February/101987.html drivers/gpu/drm/amd/amdgpu/amdgpu_display.c:127 amdgpu_flip_work_func() warn: should this be 'repcnt == -1' drivers/gpu/drm/amd/amdgpu/amdgpu_display.c:136 amdgpu_flip_work_func() error: double unlock 'spin_lock:&crtc->dev->event_lock' drivers/gpu/drm/amd/amdgpu/amdgpu_display.c:136 amdgpu_flip_work_func() error: double unlock 'irqsave:flags' This patch fixes both reported problems: Change post-decrement of repcnt to pre-decrement, so it can't underflow anymore, but still performs up to three repetitions - three is the maximum one could expect in practice. Move the spin_unlock_irqrestore to where it actually belongs. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com> Cc: <stable@vger.kernel.org> # 4.4+ Cc: Michel Dänzer <michel.daenzer@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> --- drivers/gpu/drm/radeon/radeon_display.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)