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

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Date:   Tue, 14 Feb 2023 13:56:12 -0800
From:   Rob Clark <robdclark@...il.com>
To:     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>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        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 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)

BR,
-R

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