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

[Adam Thiede]

On 10/1/24 13:02, Jason-JH Lin (林睿祥) wrote:
> On Tue, 2024-10-01 at 08:55 +0000, CK Hu (胡俊光) wrote:
>> Hi, Jason:
>> 
>> Would you clarify this problem?
>> 
> 
> OK~
> 
>> 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;
> 
> Hi Adam,
> 
> Could you print out the "fmt", "state->base.fb->format-
>>has_alpha", "state->base.alpha" and "con" here?
> 
> pr_info("fmt:0x%x, has_alpha:0x%x, alpha:0x%x, con:0x%x \n",
>          fmt, state->base.fb->format->has_alpha,
>          state->base.alpha, con);
> 
> I'm not sure if it's the color format setting problem, maybe there is
> something wire configuration here, such as XRGB8888 with alpha or
> ARGB8888 without alpha.
> 
> So I want these information to compare with my MT8188. Thanks!
> 
> Regards,
> Jason-JH.Lin
> 
Jason, thank you for your timely reply. I added the code you provided to 
my patch, and now get this line on endless repeat in dmesg:

fmt:0x34325258, has_alpha:0x0, alpha:0xffff, con:0x2000

This line also shows up sometimes in there, but I have no idea what 
triggers it.

fmt:0x34325241, has_alpha:0x1, alpha:0xffff, con:0x21ff

Does that help?

-Adam

>> > > +}
>> > >   
>> > >   /* 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
> 
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