Overlay issues

[Cornij, Nikola]

[AMD Official Use Only - Approved for External Use]

Thanks for the suggestion, Simon.

Improved the patch, now in the process of getting it reviewed internally. It'll be posted for upstream thereafter.


-----Original Message-----
From: Simon Ser <contact at emersion.fr> 
Sent: Monday, February 22, 2021 5:31 PM
To: Cornij, Nikola <Nikola.Cornij at amd.com>
Cc: Alex Deucher <alexdeucher at gmail.com>; Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>; Wentland, Harry <Harry.Wentland at amd.com>; amd-gfx list <amd-gfx at lists.freedesktop.org>
Subject: RE: Overlay issues

On Monday, February 22nd, 2021 at 9:59 PM, Cornij, Nikola <Nikola.Cornij at amd.com> wrote:

> [AMD Official Use Only - Approved for External Use]
>
> Hi Simon,
>
> Yes, I did have a chance to wrap this up, indeed :-)
>
> It turned out this and other similar setup was hitting a legit HW 
> limitation. I added a patch (please see attached) that'd fail this 
> config at validation time. The patch has been merged for upstreaming 
> at the beginning of February time-frame, not sure if it made it to the 
> public repo by now.

Excellent! I don't see the patch in agd5f/drm-next yet, but it'll probably show up soon.

Thanks for fixing this!

One small nit: if possible, add some drm_dbg_atomic() calls explaining the error right before returning -EINVAL. This is very valuable when debugging user-space applications and trying to figure out why the kernel rejects an atomic commit.