linux-kernel - Re: [PATCH 3/7] drm/msm/dpu: Always flush the slave INTF on the CTL

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Date: Tue, 23 Apr 2024 11:40:30 -0700
From: Abhinav Kumar <quic_abhinavk@...cinc.com>
To: Marijn Suijten <marijn.suijten@...ainline.org>,
        Rob Clark
	<robdclark@...il.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean
 Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter
	<daniel@...ll.ch>,
        Archit Taneja <architt@...eaurora.org>,
        Chandan Uddaraju
	<chandanu@...eaurora.org>,
        Vinod Koul <vkoul@...nel.org>,
        Sravanthi
 Kollukuduru <skolluku@...eaurora.org>
CC: <linux-arm-msm@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Jordan
 Crouse <jordan@...micpenguin.net>,
        Rajesh Yadav <ryadav@...eaurora.org>,
        Jeykumar Sankaran <jsanka@...eaurora.org>,
        <~postmarketos/upstreaming@...ts.sr.ht>,
        AngeloGioacchino Del Regno
	<angelogioacchino.delregno@...labora.com>,
        Konrad Dybcio
	<konrad.dybcio@...aro.org>,
        Martin Botka <martin.botka@...ainline.org>,
        Jami
 Kettunen <jami.kettunen@...ainline.org>
Subject: Re: [PATCH 3/7] drm/msm/dpu: Always flush the slave INTF on the CTL



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@...ainline.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@...cinc.com>