Re: [PATCH v3 6/9] drm/bridge: ti-sn65dsi86: Use 18-bit DP if we can

Doug Anderson
2020-07-10T01:38:49Z

Hi,

On Thu, Jul 9, 2020 at 6:19 PM Steev Klimaszewski <steev@gentoo.org> wrote:
>
> Hi Doug,
>
> I've been testing 5.8 and linux-next on the Lenovo Yoga C630, and with this patch applied, there is really bad banding on the display.
>
> I'm really bad at explaining it, but you can see the differences in the following:
>
> 24bit (pre-5.8) - https://dev.gentoo.org/~steev/files/image0.jpg
>
> 18bit (5.8/linux-next) - https://dev.gentoo.org/~steev/files/image1.jpg

Presumably this means that your panel is defined improperly? If the
panel reports that it's a 6 bits per pixel panel but it's actually an
8 bits per pixel panel then you'll run into this problem.

I would have to assume you have a bunch of out of tree patches to
support your hardware since I don't see any device trees in linuxnext
(other than cheza) that use this bridge chip. Otherwise I could try
to check and confirm that was the problem.

-Doug