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

[Yassine Oudjana]

On 03/10/2024 8:17 am, Jason-JH Lin (林睿祥) wrote:
>> Jason:
>> That is a lot of information, and quite above my head! Thank you
>> though.
>>
>> I should note that the log items I sent you are from the "good"
>> kernel -
>> 6.11 with the commit reverted. Here is a much longer set of logs:
>> https://termbin.com/co6v
>>
>> I've rebuild 6.11 with the log statement enabled and the "bad"
>> behavior.
>> Here is a dmesg from that: https://termbin.com/xiev
>>
> Hi Adam,
> 
> I think something wrong with your dmesg links, both logs look the same.
> We should see this log in the "bad" one:
> fmt:0x34325258, has_alpha:0x0, alpha:0xffff, con:0x2000
> 
> But anyway, I think the reason for the downgrade is clear enough to me.
> So let's try to figure out the solution.
> 
>> These logs are both from `dmesg`.
>>
>> I'm fairly certain I've built with the patch you referenced enabled.
>> The
>> kernels I run are just release kernels, not RCs or git branches or
>> anything. The mainline v6.11 kernel is the one that has this problem.
>> If
>> that patch has been merged into 6.11 (which, looks like it has) then
>> it's in the kernel I'm building.
> 
> Got it.
> Then OVL_CONST_BLEND might be the unsupported configuration in MT8173,
> I think we should remove the XRGB8888 format for MT8173.

I've carried patches that add MT6735 support in my tree for a while and 
MT6735 broke as well with this patch. Turns out MT6735's OVL doesn't 
have the CONST_BLEND bit. It's highly likely MT8173 also doesn't since 
MT8173's DISPSYS is very similar to MT6735's.

> 
> Could you please try this modification and see if it'll change to use
> others supported format to show the text?
> 
> --- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
> @@ -102,12 +102,9 @@ static inline bool is_10bit_rgb(u32 fmt)
>   }
> 
>   static const u32 mt8173_formats[] = {
> -       DRM_FORMAT_XRGB8888,
>          DRM_FORMAT_ARGB8888,
> -       DRM_FORMAT_BGRX8888,
>          DRM_FORMAT_BGRA8888,
>          DRM_FORMAT_ABGR8888,
> -       DRM_FORMAT_XBGR8888,
>          DRM_FORMAT_RGB888,
>          DRM_FORMAT_BGR888,
>          DRM_FORMAT_RGB565,
> 
> 
> Regards,
> Jason-JH.Lin
> 
>>
>> - Adam Thiede