| Message ID | 20181221031053.240161-1-yuzhao@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/3] drm/amd: fix race in page flip job | expand |
On 2018-12-21 4:10 a.m., Yu Zhao wrote: > Fix race between page flip job submission and completion. We invoke > page_flip callback to submit page flip job to GPU first and then set > pflip_status. If GPU fires page flip done irq in between, its handler > won't see the correct pflip_status thus will refuse to notify the job > completion. The job will eventually times out. > > Reverse the order of calling page_flip and setting pflip_status to > fix the race. There is no race, amdgpu_crtc->pflip_status is protected by dev->event_lock.
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c index 686a26de50f9..e309d26170db 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c @@ -105,11 +105,11 @@ static void amdgpu_display_flip_work_func(struct work_struct *__work) /* We borrow the event spin lock for protecting flip_status */ spin_lock_irqsave(&crtc->dev->event_lock, flags); + /* Set the flip status */ + amdgpu_crtc->pflip_status = AMDGPU_FLIP_SUBMITTED; /* Do the flip (mmio) */ adev->mode_info.funcs->page_flip(adev, work->crtc_id, work->base, work->async); - /* Set the flip status */ - amdgpu_crtc->pflip_status = AMDGPU_FLIP_SUBMITTED; spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
Fix race between page flip job submission and completion. We invoke page_flip callback to submit page flip job to GPU first and then set pflip_status. If GPU fires page flip done irq in between, its handler won't see the correct pflip_status thus will refuse to notify the job completion. The job will eventually times out. Reverse the order of calling page_flip and setting pflip_status to fix the race. Signed-off-by: Yu Zhao <yuzhao@google.com> --- drivers/gpu/drm/amd/amdgpu/amdgpu_display.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)