[PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached

[AngeloGioacchino Del Regno]

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 at chromium.org>
> Reviewed-by: Guillaume Ranquet <granquet at baylibre.com>

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