Re: [PATCH] drm/msm/dpu: Don't always set merge_3d pending flush

[Dmitry Baryshkov]

On Wed, Oct 09, 2024 at 08:41:13PM GMT, Jessica Zhang wrote:
> Don't set the merge_3d pending flush bits if the mode_3d is
> BLEND_3D_NONE.
> 
> Always flushing merge_3d can cause timeout issues when there are
> multiple commits with concurrent writeback enabled.
> 
> This is because the video phys enc waits for the hw_ctl flush register
> to be completely cleared [1] in its wait_for_commit_done(), but the WB
> encoder always sets the merge_3d pending flush during each commit
> regardless of if the merge_3d is actually active.
> 
> This means that the hw_ctl flush register will never be 0 when there are
> multiple CWB commits and the video phys enc will hit vblank timeout
> errors after the first CWB commit.

>From this description, wouldn't it be more correct to always set
intf_cfg.merge_3d in WB code (even if mode_3d is NONE)?

> [1] commit fe9df3f50c39 ("drm/msm/dpu: add real wait_for_commit_done()")
> 
> Fixes: 3e79527a33a8 ("drm/msm/dpu: enable merge_3d support on sm8150/sm8250")
> Fixes: d7d0e73f7de3 ("drm/msm/dpu: introduce the dpu_encoder_phys_* for writeback")
> Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 5 ++++-
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c  | 5 ++++-
>  2 files changed, 8 insertions(+), 2 deletions(-)
> 

-- 
With best wishes
Dmitry