| Message ID | 20231201014101.15802-1-quic_parellan@quicinc.com |
|---|---|
| Headers | show |
| Series | Stabilize use of vblank_refcount | expand |
On 11/30/2023 11:45 PM, Dmitry Baryshkov wrote: > On Fri, 1 Dec 2023 at 03:41, Paloma Arellano <quic_parellan@quicinc.com> wrote: >> >> When the irq callback returns a value other than zero, >> modify vblank_refcount by performing the inverse >> operation of its corresponding if-else condition. > > I think it might be better to follow Bjorn's suggestion: once we have > the lock, we don't need atomics at all. > Then you rearrange the code to set the new value after getting return > code from dpu_core_irq_register_callback() / > dpu_core_irq_unregister_callback(). > Even if we drop the atomics, we will have to replace it with a simple refcount. The refcount checks will be before calling dpu_core_irq_register_callback() / dpu_core_irq_unregister_callback(). So we will still need the corresponding inverse refcount when either of those calls fail but just that they wont be atomics. Am I missing something here? >> >> Signed-off-by: Paloma Arellano <quic_parellan@quicinc.com> >> --- >> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 9 +++++++-- >> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 9 +++++++-- >> 2 files changed, 14 insertions(+), 4 deletions(-) >
There is currently a race condition occuring when accessing vblank_refcount. Therefore, vblank irq timeouts may occur. Avoid any vblank irq timeouts by stablizing the use of vblank_refcount. Changes from prior versions: v2: - Slightly changed wording of patch #2 commit message v3: - Mistakenly did not change wording of patch #2 in last version. It is done now. Paloma Arellano (2): drm/msm/dpu: Modify vblank_refcount if error in callback drm/msm/dpu: Add mutex lock in control vblank irq drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 6 ++++++ drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h | 6 ++++++ drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 11 +++++++++-- drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 11 +++++++++-- 4 files changed, 30 insertions(+), 4 deletions(-)