linux-kernel - Re: [RFC PATCH 3/6] drm/msm/dpu1: Wire up DSC mask for active CTL configuration

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Date:   Fri, 16 Dec 2022 14:20:52 -0800
From:   Abhinav Kumar <quic_abhinavk@...cinc.com>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        <phone-devel@...r.kernel.org>, Rob Clark <robdclark@...il.com>,
        Vinod Koul <vkoul@...nel.org>,
        <~postmarketos/upstreaming@...ts.sr.ht>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Martin Botka <martin.botka@...ainline.org>,
        Jami Kettunen <jami.kettunen@...ainline.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        "Stephen Boyd" <swboyd@...omium.org>,
        Bjorn Andersson <andersson@...nel.org>,
        "Jessica Zhang" <quic_jesszhan@...cinc.com>,
        Ville Syrjälä <ville.syrjala@...ux.intel.com>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>,
        "Jani Nikula" <jani.nikula@...el.com>,
        sunliming <sunliming@...inos.cn>,
        "Sam Ravnborg" <sam@...nborg.org>,
        Haowen Bai <baihaowen@...zu.com>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Loic Poulain <loic.poulain@...aro.org>,
        "Vinod Polimera" <quic_vpolimer@...cinc.com>,
        Douglas Anderson <dianders@...omium.org>,
        Vladimir Lypak <vladimir.lypak@...il.com>,
        <linux-arm-msm@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 3/6] drm/msm/dpu1: Wire up DSC mask for active CTL
 configuration



On 12/14/2022 5:08 PM, Dmitry Baryshkov wrote:
> On 14/12/2022 21:30, Marijn Suijten wrote:
>> On 2022-12-14 20:43:29, Dmitry Baryshkov wrote:
>>> On 14/12/2022 01:22, Marijn Suijten wrote:
>>>> Active CTLs have to configure what DSC block(s) have to be enabled, and
>>>> what DSC block(s) have to be flushed; this value was initialized to 
>>>> zero
>>>> resulting in the necessary register writes to never happen (or would
>>>> write zero otherwise).  This seems to have gotten lost in the DSC 
>>>> v4->v5
>>>> series while refactoring how the combination with merge_3d was handled.
>>>>
>>>> Fixes: 58dca9810749 ("drm/msm/disp/dpu1: Add support for DSC in 
>>>> encoder")
>>>> Signed-off-by: Marijn Suijten <marijn.suijten@...ainline.org>
>>>> ---
>>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c | 1 +
>>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 1 +
>>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c  | 2 ++
>>>>    3 files changed, 4 insertions(+)
>>>>
>>>> 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 ae28b2b93e69..35791f93c33d 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
>>>> @@ -61,6 +61,7 @@ static void _dpu_encoder_phys_cmd_update_intf_cfg(
>>>>        intf_cfg.intf_mode_sel = DPU_CTL_MODE_SEL_CMD;
>>>>        intf_cfg.stream_sel = cmd_enc->stream_sel;
>>>>        intf_cfg.mode_3d = 
>>>> dpu_encoder_helper_get_3d_blend_mode(phys_enc);
>>>> +    intf_cfg.dsc = dpu_encoder_helper_get_dsc(phys_enc);
>>>>        ctl->ops.setup_intf_cfg(ctl, &intf_cfg);
>>>>        /* setup which pp blk will connect to this intf */
>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c 
>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
>>>> index 0f71e8fe7be7..9ee3a7306a5f 100644
>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
>>>> @@ -274,6 +274,7 @@ static void 
>>>> dpu_encoder_phys_vid_setup_timing_engine(
>>>>        intf_cfg.intf_mode_sel = DPU_CTL_MODE_SEL_VID;
>>>>        intf_cfg.stream_sel = 0; /* Don't care value for video mode */
>>>>        intf_cfg.mode_3d = 
>>>> dpu_encoder_helper_get_3d_blend_mode(phys_enc);
>>>> +    intf_cfg.dsc = dpu_encoder_helper_get_dsc(phys_enc);
>>>>        if (phys_enc->hw_pp->merge_3d)
>>>>            intf_cfg.merge_3d = phys_enc->hw_pp->merge_3d->idx;
>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c 
>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>>>> index 7cbcef6efe17..92ddf9995b37 100644
>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_wb.c
>>>> @@ -209,6 +209,7 @@ static void dpu_encoder_phys_wb_setup_cdp(struct 
>>>> dpu_encoder_phys *phys_enc)
>>>>            intf_cfg.intf = DPU_NONE;
>>>>            intf_cfg.wb = hw_wb->idx;
>>>> +        intf_cfg.dsc = dpu_encoder_helper_get_dsc(phys_enc);
>>>
>>> We usually don't have DSC with the writeback, don't we?
>>
>> I am unsure so ended up adding them in writeback regardless.  Downstream
>> uses a separate callback to process intf_cfg.dsc instead of going
>> through setup_intf_cfg().
>>
>> To prevent these from being missed again (in the case of copy&paste),
>> how about instead having some function that sets up intf_cfg with these
>> default values from a phys_enc?  That way most of this remains oblivious
>> to the caller.
> 
> I'm not sure this is possible. E.g. intf_cfg.dsc should not be set for 
> the WB.
> 

Although this change is harmless because 
dpu_encoder_helper_get_dsc(phys_enc) will not return a valid DSC mask 
for the WB encoder, hence the setup_intf_cfg will just skip the DSC 
programming, I also agree that we can skip setting the intf_cfg.dsc for 
the writeback encoder in this patch.

>>
>> On the same note, that callback on non-DPU_CTL_ACTIVE_CFG hardware
>> doesn't use the intf_cfg.dsc member anyway, but it was again added to
>> keep the blocks somewhat consistent (in case it ever becomes used?).
>>
>>>>            if (mode_3d && hw_pp && hw_pp->merge_3d)
>>>>                intf_cfg.merge_3d = hw_pp->merge_3d->idx;
>>>> @@ -230,6 +231,7 @@ static void dpu_encoder_phys_wb_setup_cdp(struct 
>>>> dpu_encoder_phys *phys_enc)
>>>>            intf_cfg.wb = hw_wb->idx;
>>>>            intf_cfg.mode_3d =
>>>>                dpu_encoder_helper_get_3d_blend_mode(phys_enc);
>>>> +        intf_cfg.dsc = dpu_encoder_helper_get_dsc(phys_enc);
>>>>            phys_enc->hw_ctl->ops.setup_intf_cfg(phys_enc->hw_ctl, 
>>>> &intf_cfg);
>>>>        }
>>>>    }
>>
>> - Marijn
>