linux-kernel - Re: [Freedreno] [PATCH 09/14] drm/msm/a6xx: Fix some A619 tunables

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Message-ID: <48364c3f-699d-ce14-37c4-53bf4a90bc23@linaro.org>
Date:   Tue, 14 Feb 2023 12:25:01 +0100
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     linux-arm-msm@...r.kernel.org, andersson@...nel.org,
        agross@...nel.org, krzysztof.kozlowski@...aro.org,
        freedreno@...ts.freedesktop.org,
        Akhil P Oommen <quic_akhilpo@...cinc.com>,
        David Airlie <airlied@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        dri-devel@...ts.freedesktop.org,
        Douglas Anderson <dianders@...omium.org>,
        Rob Clark <robdclark@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        marijn.suijten@...ainline.org, Sean Paul <sean@...rly.run>,
        Chia-I Wu <olvaffe@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [Freedreno] [PATCH 09/14] drm/msm/a6xx: Fix some A619 tunables



On 8.02.2023 19:21, Jordan Crouse wrote:
> On Thu, Jan 26, 2023 at 04:16:13PM +0100, Konrad Dybcio wrote:
>> Adreno 619 expects some tunables to be set differently. Make up for it.
>>
>> Fixes: b7616b5c69e6 ("drm/msm/adreno: Add A619 support")
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---
>>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> index 7a480705f407..f34ab3f39f09 100644
>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> @@ -1171,6 +1171,8 @@ static int hw_init(struct msm_gpu *gpu)
>>                 gpu_write(gpu, REG_A6XX_PC_DBG_ECO_CNTL, 0x00200200);
>>         else if (adreno_is_a650(adreno_gpu) || adreno_is_a660(adreno_gpu))
>>                 gpu_write(gpu, REG_A6XX_PC_DBG_ECO_CNTL, 0x00300200);
>> +       else if (adreno_is_a619(adreno_gpu))
>> +               gpu_write(gpu, REG_A6XX_PC_DBG_ECO_CNTL, 0x00018000);
>>         else if (adreno_is_a610(adreno_gpu))
>>                 gpu_write(gpu, REG_A6XX_PC_DBG_ECO_CNTL, 0x00080000);
>>         else
>> @@ -1188,7 +1190,9 @@ static int hw_init(struct msm_gpu *gpu)
>>         a6xx_set_ubwc_config(gpu);
>>
>>         /* Enable fault detection */
>> -       if (adreno_is_a610(adreno_gpu))
>> +       if (adreno_is_a619(adreno_gpu))
>> +               gpu_write(gpu, REG_A6XX_RBBM_INTERFACE_HANG_INT_CNTL, (1 << 30) | 0x3fffff);
>> +       else if (adreno_is_a610(adreno_gpu))
>>                 gpu_write(gpu, REG_A6XX_RBBM_INTERFACE_HANG_INT_CNTL, (1 << 30) | 0x3ffff);
>>         else
>>                 gpu_write(gpu, REG_A6XX_RBBM_INTERFACE_HANG_INT_CNTL, (1 << 30) | 0x1fffff);
> 
> The number appended to the register is the number of clock ticks to wait
> before declaring a hang. 0x3fffff happens to be the largest value that
> can be set for the a6xx family (excepting the 610 which, IIRC, used older
> hardware that had a smaller field for the counter).
Makes sense!

Downstream the
> number would creep up over time as unexplained hangs were discovered and
> diagnosed or covered up as "just wait longer".
lol..

> 
> So in theory you could leave this with the "default value" or even bump
> up the default value to 0x3fffff for all targets if you wanted to. An
> alternate solution (that downstream does) is to put this as a
> pre-defined configuration in gpulist[].
I'm not sure it's a good idea to let things loose, as that may let some
bugs slip through.. Perhaps let's leave that as-is until we have a seriously
otherwise-unresolvable situation..

Konrad
> 
> Jordan