[PATCH v3 13/14] drm/mediatek: Support DRM plane alpha in OVL

[CK Hu (胡俊光)]

Hi, Jason:

Would you clarify this problem?

Regards,
CK

On Mon, 2024-09-30 at 12:48 -0500, Adam Thiede wrote:
>  	 
> External email : Please do not click links or open attachments until you have verified the sender or the content.
>  On 6/19/24 11:38, Hsiao Chien Sung via B4 Relay wrote:
> > From: Hsiao Chien Sung <shawn.sung at mediatek.com>
> > 
> > Set the plane alpha according to DRM plane property.
> > 
> > Reviewed-by: CK Hu <ck.hu at mediatek.com>
> > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
> > Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
> > Signed-off-by: Hsiao Chien Sung <shawn.sung at mediatek.com>
> > ---
> >   drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > index 943db4f1bd6b..4b370bc0746d 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> > @@ -458,8 +458,10 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
> >   }
> >   
> >   con = ovl_fmt_convert(ovl, fmt);
> > -if (state->base.fb && state->base.fb->format->has_alpha)
> > -con |= OVL_CON_AEN | OVL_CON_ALPHA;
> > +if (state->base.fb) {
> > +con |= OVL_CON_AEN;
> > +con |= state->base.alpha & OVL_CON_ALPHA;
> > +}
> >   
> >   /* CONST_BLD must be enabled for XRGB formats although the alpha channel
> >    * can be ignored, or OVL will still read the value from memory.
> > 
> Hello, I believe that this commit has caused a problem for my Lenovo 
> C330 Chromebook running postmarketOS.
> 
> With kernel 6.11 this device didn't show any text on the tty or splash 
> screen during booting, but graphical environments (wayland, xorg) do 
> appear. With a few bisects I found it to be this commit. With it 
> reverted I'm able to get text on the tty again.
> 
> The kernel config is here: 
> https://gitlab.com/adamthiede/pmaports/-/tree/mt8173-611/device/community/linux-postmarketos-mediatek-mt8173/
> To be perfectly clear, this device is not running Chrome OS.
> 
> I'm still rather new at this so it's also likely I got something wrong 
> or have a bad configuration option. If there is any more information I 
> can provide please let me know. Thank you.
> 
> - Adam Thiede