Message-ID: <e2e02a7b-0e0c-e0f8-df49-ae2ea27c4440@collabora.com>
Date:   Thu, 2 Feb 2023 10:14:40 +0100
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Subject: Re: [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if
 bridge is attached
Content-Language: en-US
To:     Chen-Yu Tsai <wenst@chromium.org>,
        Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     dri-devel@lists.freedesktop.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        Guillaume Ranquet <granquet@baylibre.com>
References: <20230202045734.2773503-1-wenst@chromium.org>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20230202045734.2773503-1-wenst@chromium.org>
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Precedence: bulk

Il 02/02/23 05:57, Chen-Yu Tsai ha scritto:
> The MediaTek DisplayPort interface bridge driver starts its interrupts
> as soon as its probed. However when the interrupts trigger the bridge
> might not have been attached to a DRM device. As drm_helper_hpd_irq_event()
> does not check whether the passed in drm_device is valid or not, a NULL
> pointer passed in results in a kernel NULL pointer dereference in it.
> 
> Check whether the bridge is attached and only trigger an HPD event if
> it is.
> 
> Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> Reviewed-by: Guillaume Ranquet <granquet@baylibre.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>