linux-kernel - Re: [PATCH v2 10/14] drm/msm/a6xx: Fix up A6XX protected registers

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Date:   Wed, 15 Feb 2023 02:10:02 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Rob Clark <robdclark@...il.com>,
        Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     linux-arm-msm@...r.kernel.org, andersson@...nel.org,
        agross@...nel.org, marijn.suijten@...ainline.org,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>,
        Chia-I Wu <olvaffe@...il.com>,
        Douglas Anderson <dianders@...omium.org>,
        Jonathan Marek <jonathan@...ek.ca>,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 10/14] drm/msm/a6xx: Fix up A6XX protected registers

On 14/02/2023 23:56, Rob Clark wrote:
> On Tue, Feb 14, 2023 at 9:32 AM Konrad Dybcio <konrad.dybcio@...aro.org> wrote:
>>
>> One of the protected ranges was too small (compared to the data we
>> have downstream). Fix it.
>>
>> Fixes: 408434036958 ("drm/msm/a6xx: update/fix CP_PROTECT initialization")
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---
>>   drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> index 503c750216e6..d6b38bfdb3b4 100644
>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> @@ -690,7 +690,7 @@ static const u32 a6xx_protect[] = {
>>          A6XX_PROTECT_NORDWR(0x00800, 0x0082),
>>          A6XX_PROTECT_NORDWR(0x008a0, 0x0008),
>>          A6XX_PROTECT_NORDWR(0x008ab, 0x0024),
>> -       A6XX_PROTECT_RDONLY(0x008de, 0x00ae),
>> +       A6XX_PROTECT_RDONLY(0x008d0, 0x00bc),
> 
> Nak, this is intentional, we need userspace to be able to configure
> the CP counters.  Otherwise this would break fdperf, perfetto, etc
> 
> (although maybe we should comment where we diverge from downstream)

Yes, please. Otherwise it is extremely hard to understand the reason for 
diversion between the vendor driver and our one.

> 
> BR,
> -R
> 
>>          A6XX_PROTECT_NORDWR(0x00900, 0x004d),
>>          A6XX_PROTECT_NORDWR(0x0098d, 0x0272),
>>          A6XX_PROTECT_NORDWR(0x00e00, 0x0001),
>> --
>> 2.39.1
>>

-- 
With best wishes
Dmitry