[PATCH] drm/tilcdc: Set preferred depth

[Frej Drejhammar]

Hi Kevin,

Kevin Hao <haokexin at gmail.com> writes:

> But after kernel commit c91acda3a380, the FB will not be created
> successfully due to the check of the valid pixel format. Then the bpp
> is set to 24, but the 'depth = 16' and 'bpp = 24' combo is not a valid
> pixel format.
>
> Fix this issue by explicitly setting the preferred_depth in this driver.
> With this change, the modesetting driver would choose the correct
> depth/bpp combo based on our setting in xorg.conf.

Check the fix in [1], with it not only does the X-server work with a
color depth of 16 bits, it also enables the use of a 24 bit color depth.

As I'm the author of the solution in [1] I'm partial to it as it is a
more general solution to the regression. I have no standing in this
community as [1] is my first contribution to the DRM system, but if I
had, I would NAK this patch as it only fixes the regression for one
driver and does not enable the use of a 24 bit color depth which is
something the hardware is capable of.

Best regards,

--Frej

[1] https://lore.kernel.org/all/e7ef6d422365986f49746b596735f7a0b939574d.1710698387.git.frej.drejhammar@gmail.com/