[PATCH v11 1/5] drm/mediatek: ovl: Fix XRGB format breakage for blend_modes unsupported SoCs

[AngeloGioacchino Del Regno]

Il 09/10/24 05:46, Jason-JH.Lin ha scritto:
> OVL_CON_AEN is for alpha blending enable.
> For the SoC that is supported the blend_modes, OVL_CON_AEN will always
> enabled to use constant alpha and then use the ignore_pixel_alpha bit
> to do the alpha blending for XRGB8888 format.
> Note that ignore pixel alpha bit is not supported if the SoC is not
> supported the blend_modes.
> So it will break the original setting of XRGB8888 format for the
> blend_modes unsupported SoCs, such as MT8173.
> 
> To fix the downgrade issue, enable alpha blending only when a valid
> blend_mode or has_alpha is set.
> 
> Fixes: bc46eb5d5d77 ("drm/mediatek: Support DRM plane alpha in OVL")
> Signed-off-by: Jason-JH.Lin <jason-jh.lin at mediatek.com>
> Reviewed-by: CK Hu <ck.hu at mediatek.com>

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