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References: <20230221153740.1620529-1-angelogioacchino.delregno@collabora.com> <20230221153740.1620529-9-angelogioacchino.delregno@collabora.com>
In-Reply-To: <20230221153740.1620529-9-angelogioacchino.delregno@collabora.com>
From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Wed, 22 Feb 2023 12:11:18 +0800
Message-ID: <CAGXv+5Hc0qceN3Cr89ZF8K9-EwqF7v26qsdRS2mE_FE_nr7OiA@mail.gmail.com>
Subject: Re: [PATCH v2 08/10] drm/panfrost: Add the MT8192 GPU ID
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
Cc:     airlied@gmail.com, daniel@ffwll.ch, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, steven.price@arm.com,
        alyssa.rosenzweig@collabora.com, matthias.bgg@gmail.com,
        robh@kernel.org, dri-devel@lists.freedesktop.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org
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On Tue, Feb 21, 2023 at 11:37 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> wrote:
>
> From: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
>
> MediaTek MT8192 has a Mali-G57 with a special GPU ID. Add its GPU ID,
> but treat it as otherwise identical to a standard Mali-G57.
>
> We do _not_ fix up the GPU ID here -- userspace needs to be aware of the
> special GPU ID, in case we find functional differences between
> MediaTek's implementation and the standard Mali-G57 down the line.

> Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Steven Price <steven.price@arm.com>

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>

FYI MT8195 has a minor revision for Mali-G57. See https://crrev.com/c/2834981
The commit doesn't say what issues were resolved or still linger though.

> ---
>  drivers/gpu/drm/panfrost/panfrost_gpu.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> index 6452e4e900dd..d28b99732dde 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
> @@ -204,6 +204,14 @@ static const struct panfrost_model gpu_models[] = {
>
>         GPU_MODEL(g57, 0x9001,
>                 GPU_REV(g57, 0, 0)),
> +
> +       /* MediaTek MT8192 has a Mali-G57 with a different GPU ID from the
> +        * standard. Arm's driver does not appear to handle this model.
> +        * ChromeOS has a hack downstream for it. Treat it as equivalent to
> +        * standard Mali-G57 for now.
> +        */
> +       GPU_MODEL(g57, 0x9003,
> +               GPU_REV(g57, 0, 0)),
>  };
>
>  static void panfrost_gpu_init_features(struct panfrost_device *pfdev)
> --
> 2.39.2
>