linux-kernel - Re: [PATCH v2 3/4] drm/msm/dpu: Add DPU_INTF_DATA

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Message-ID: <1d7ccb5f-55c2-3b3a-df97-2c17beffabfc@quicinc.com>
Date:   Mon, 8 May 2023 14:46:10 -0700
From:   Jessica Zhang <quic_jesszhan@...cinc.com>
To:     Marijn Suijten <marijn.suijten@...ainline.org>
CC:     Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        <linux-arm-msm@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/4] drm/msm/dpu: Add DPU_INTF_DATA_COMPRESS feature
 flag



On 5/7/2023 9:00 AM, Marijn Suijten wrote:
> On 2023-05-05 14:23:50, Jessica Zhang wrote:
>> Add DATA_COMPRESS feature flag to DPU INTF block.
>>
>> In DPU 7.x and later, DSC/DCE enablement registers have been moved from
>> PINGPONG to INTF.
>>
>> As core_rev (and related macros) was removed from the dpu_kms struct, the
>> most straightforward way to indicate the presence of this register would be
>> to have a feature flag.
> 
> Irrelevant.  Even though core_rev was still in mainline until recently,
> we always hardcoded the features in the catalog and only used core_rev
> to select a dpu_mdss_cfg catalog entry.  There is no "if version >= X
> then enable feature Y" logic, this manually-enabled feature flag is the
> only, correct way to do it.

Hi Marijn,

Understood. FWIW, if we do find more register bit-level differences 
between HW versions in the future, it might make more sense to keep the 
HW catalog small and bring core_rev back, rather than keep adding these 
kinds of small differences to caps.

Thanks,

Jessica Zhang

> 
>> Changes in v2:
>> - Changed has_data_compress dpu_cap to a DATA_COMPRESS INTF feature flag
>>
>> Signed-off-by: Jessica Zhang <quic_jesszhan@...cinc.com>
> 
> Reviewed-by: Marijn Suijten <marijn.suijten@...ainline.org>
> 
>> ---
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c | 2 +-
>>   drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h | 2 ++
>>   2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
>> index 7944481d0a33..c74051906d05 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.c
>> @@ -104,7 +104,7 @@
>>   #define INTF_SC7180_MASK \
>>   	(BIT(DPU_INTF_INPUT_CTRL) | BIT(DPU_INTF_TE) | BIT(DPU_INTF_STATUS_SUPPORTED))
>>   
>> -#define INTF_SC7280_MASK INTF_SC7180_MASK | BIT(DPU_DATA_HCTL_EN)
>> +#define INTF_SC7280_MASK INTF_SC7180_MASK | BIT(DPU_DATA_HCTL_EN) | BIT(DPU_INTF_DATA_COMPRESS)
> 
> Konrad: Your SM6350/SM6375 series v3 [1] switched from INTF_SC7180_MASK
> to INTF_SC7280_MASK to enable HCTL on SM6375, but that will now
> erroneously also receive this feature flag and write the new
> DATA_COMPESS mask even if it's DPU 6.9 (< 7.x where it got added).
> 
> [1]: https://lore.kernel.org/linux-arm-msm/80b46fcb-d6d0-1998-c273-5401fa924c7d@linaro.org/T/#u
> 
> Depending on who lands first, this flag should be split.
> 
> I still see value in inlining and removing these defines, though that
> brings a host of other complexity.
> 
> - Marijn
> 
>>   #define WB_SM8250_MASK (BIT(DPU_WB_LINE_MODE) | \
>>   			 BIT(DPU_WB_UBWC) | \
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>> index 4eda2cc847ef..01c65f940f2a 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>> @@ -185,6 +185,7 @@ enum {
>>    * @DPU_DATA_HCTL_EN                Allows data to be transferred at different rate
>>    *                                  than video timing
>>    * @DPU_INTF_STATUS_SUPPORTED       INTF block has INTF_STATUS register
>> + * @DPU_INTF_DATA_COMPRESS          INTF block has DATA_COMPRESS register
>>    * @DPU_INTF_MAX
>>    */
>>   enum {
>> @@ -192,6 +193,7 @@ enum {
>>   	DPU_INTF_TE,
>>   	DPU_DATA_HCTL_EN,
>>   	DPU_INTF_STATUS_SUPPORTED,
>> +	DPU_INTF_DATA_COMPRESS,
>>   	DPU_INTF_MAX
>>   };
>>   
>>
>> -- 
>> 2.40.1
>>