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

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Date:   Wed, 15 Feb 2023 01:38:48 +0100
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Rob Clark <robdclark@...il.com>
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 15.02.2023 01:10, Dmitry Baryshkov wrote:
> 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.
+1

I am content with dropping this patch from this series, so long
as you leave a clue for others to not scratch their heads on this!

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