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Message-ID: <6a335df7-ff0b-098a-feec-45714159df04@linaro.org>
Date:   Thu, 20 Apr 2023 21:01:04 +0300
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Subject: Re: [PATCH 0/2] DPU1 GC1.8 wiring-up
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To:     Konrad Dybcio <konrad.dybcio@linaro.org>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     Marijn Suijten <marijn.suijten@somainline.org>,
        linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
References: <20230420-topic-dpu_gc-v1-0-d9d1a5e40917@linaro.org>
 <5b133c55-e4f5-bfd2-b542-a7d44313c038@linaro.org>
 <c0e0a55a-cc37-fe8a-8d8a-5fe257f99b9a@linaro.org>
 <3f3b3637-ed85-09a1-22b7-3ccd4bc929bb@quicinc.com>
 <2dff9d62-cffe-c66f-9e50-3ecd64e44d37@linaro.org>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
In-Reply-To: <2dff9d62-cffe-c66f-9e50-3ecd64e44d37@linaro.org>
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On 20/04/2023 04:36, Konrad Dybcio wrote:
> 
> 
> On 20.04.2023 03:28, Abhinav Kumar wrote:
>>
>>
>> On 4/19/2023 6:26 PM, Konrad Dybcio wrote:
>>>
>>>
>>> On 20.04.2023 03:25, Dmitry Baryshkov wrote:
>>>> On 20/04/2023 04:14, Konrad Dybcio wrote:
>>>>> Almost all SoCs from SDM845 to SM8550 inclusive feature a GC1.8
>>>>> dspp sub-block in addition to PCCv4. The other block differ a bit
>>>>> more, but none of them are supported upstream.
>>>>>
>>>>> This series adds configures the GCv1.8 on all the relevant SoCs.
>>>>
>>>> Does this mean that we will see gamma_lut support soon?
>>> No promises, my plate is not even full, it's beyond overflowing! :P
>>>
>>> Konrad
>>
>> So I think I wrote about this before during the catalog rework/fixes that the gc registers are not written to / programmed.
>>
>> If thats not done, is there any benefit to this series?
> Completeness and preparation for the code itself, if nothing else?

The usual problem is that if something is not put to use, it quickly 
rots or becomes misused for newer platforms. We have seen this with the 
some of DPU features.

In case of GC (and the freshly defined DPU_DSPP_IGC, but not used) we 
have three options:
- drop the unused GC from msm8998_sblk.
- keep things as is, single unused GC entry
- fill all the sblk with the correct information in hope that it stays 
correct

Each of these options has its own drawbacks. I have slight bias towards 
the last option, to have the information in place (as long as it is 
accurate).

-- 
With best wishes
Dmitry