linux-kernel - Re: [PATCH] drm/msm/adreno: Drop WARN_ON from patchid lookup for new GPUs

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Message-ID: <630d10c6-326a-4cdb-be6b-cd832378187b@linaro.org>
Date:   Mon, 4 Dec 2023 12:28:21 +0100
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Rob Clark <robdclark@...il.com>
Cc:     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>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        Rob Clark <robdclark@...omium.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Abel Vesa <abel.vesa@...aro.org>
Subject: Re: [PATCH] drm/msm/adreno: Drop WARN_ON from patchid lookup for new
 GPUs

On 26.10.2023 21:16, Konrad Dybcio wrote:
> 
> 
> On 10/23/23 22:20, Rob Clark wrote:
>> On Mon, Oct 23, 2023 at 12:56 PM Konrad Dybcio <konrad.dybcio@...aro.org> wrote:
>>>
>>>
>>>
>>> On 10/23/23 21:42, Rob Clark wrote:
>>>> On Mon, Oct 23, 2023 at 7:29 AM Konrad Dybcio <konrad.dybcio@...aro.org> wrote:
>>>>>
>>>>> New GPUs still use the lower 2 bytes of the chip id (in whatever form
>>>>> it comes) to signify silicon revision. Drop the warning that makes it
>>>>> sound as if that was unintended.
>>>>>
>>>>> Fixes: 90b593ce1c9e ("drm/msm/adreno: Switch to chip-id for identifying GPU")
>>>>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>>>>> ---
>>>>>    drivers/gpu/drm/msm/adreno/adreno_gpu.h | 5 -----
>>>>>    1 file changed, 5 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
>>>>> index 80b3f6312116..9a1ec42155fd 100644
>>>>> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
>>>>> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
>>>>> @@ -203,11 +203,6 @@ struct adreno_platform_config {
>>>>>
>>>>>    static inline uint8_t adreno_patchid(const struct adreno_gpu *gpu)
>>>>>    {
>>>>> -       /* It is probably ok to assume legacy "adreno_rev" format
>>>>> -        * for all a6xx devices, but probably best to limit this
>>>>> -        * to older things.
>>>>> -        */
>>>>> -       WARN_ON_ONCE(gpu->info->family >= ADRENO_6XX_GEN1);
>>>>
>>>> Maybe just change it to ADRENO_6XX_GEN4?
>>> That also applies to 700
>>
>> Then the warn is warning about what it is supposed to ;-)
>>
>> I guess this is coming from a6xx_gmu_fw_start()?  I think we need a
>> different way to construct the gmu chipid, since the point of this was
>> to not depend on the low 8b having any particular meaning.  Perhaps we
>> should just get the gmu chipid from the device table.
> Guess that could work as well..
Well, I realized that we already sorta do this..

MAJ is always set to 7 (duh)
MIN has a lookup table that will expand with future additions
PATCHID needs to vary, and that should be CHIPID & 0xff

Konrad