As we can clearly see in a downstream kernel [1], flushing the slave INTF
is skipped /only if/ the PPSPLIT topology is active.

However, when DPU was originally submitted to mainline PPSPLIT was no
longer part of it (seems to have been ripped out before submission), but
this clause was incorrectly ported from the original SDE driver.  Given
that there is no support for PPSPLIT (currently), flushing the slave
INTF should /never/ be skipped (as the `if (ppsplit && !master) goto
skip;` clause downstream never becomes true).

[1]: https://git.codelinaro.org/clo/la/platform/vendor/opensource/display-drivers/-/blob/display-kernel.lnx.5.4.r1-rel/msm/sde/sde_encoder_phys_cmd.c?ref_type=heads#L1131-1139

Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
index fc1d5736d7fc..489be1c0c704 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
@@ -448,9 +448,6 @@ static void dpu_encoder_phys_cmd_enable_helper(
 
 	_dpu_encoder_phys_cmd_pingpong_config(phys_enc);
 
-	if (!dpu_encoder_phys_cmd_is_master(phys_enc))
-		return;
-
 	ctl = phys_enc->hw_ctl;
 	ctl->ops.update_pending_flush_intf(ctl, phys_enc->hw_intf->idx);
 }

-- 
2.44.0

On 4/16/2024 4:57 PM, Marijn Suijten wrote:
> As we can clearly see in a downstream kernel [1], flushing the slave INTF
> is skipped /only if/ the PPSPLIT topology is active.
> 
> However, when DPU was originally submitted to mainline PPSPLIT was no
> longer part of it (seems to have been ripped out before submission), but
> this clause was incorrectly ported from the original SDE driver.  Given
> that there is no support for PPSPLIT (currently), flushing the slave
> INTF should /never/ be skipped (as the `if (ppsplit && !master) goto
> skip;` clause downstream never becomes true).
> 
> [1]: https://git.codelinaro.org/clo/la/platform/vendor/opensource/display-drivers/-/blob/display-kernel.lnx.5.4.r1-rel/msm/sde/sde_encoder_phys_cmd.c?ref_type=heads#L1131-1139
> 
> Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
> Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 3 ---
>   1 file changed, 3 deletions(-)
> 

Yes, I agree with this, even though I did think earlier that intf master 
flush was sufficient , I cross-checked the docs and this is the right way.


Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>

On Wed, 17 Apr 2024 at 02:57, Marijn Suijten
<marijn.suijten@somainline.org> wrote:
>
> As we can clearly see in a downstream kernel [1], flushing the slave INTF
> is skipped /only if/ the PPSPLIT topology is active.
>
> However, when DPU was originally submitted to mainline PPSPLIT was no
> longer part of it (seems to have been ripped out before submission), but
> this clause was incorrectly ported from the original SDE driver.  Given
> that there is no support for PPSPLIT (currently), flushing the slave
> INTF should /never/ be skipped (as the `if (ppsplit && !master) goto
> skip;` clause downstream never becomes true).
>
> [1]: https://git.codelinaro.org/clo/la/platform/vendor/opensource/display-drivers/-/blob/display-kernel.lnx.5.4.r1-rel/msm/sde/sde_encoder_phys_cmd.c?ref_type=heads#L1131-1139
>
> Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
> Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
> ---
>  drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 3 ---
>  1 file changed, 3 deletions(-)


Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

-- 
With best wishes
Dmitry