[amdgpu] Xorg logs spammed with failed page flip messages

[Douglas Silva]

Please read this bug report: https://bugzilla.redhat.com/show_bug.cgi?id=1645553

I'm running Ubuntu MATE 19.10 Eoan, currently with xorg-server-source 2:1.20.5+git20191008-0ubuntu1 (xorg 1:7.7+19ubuntu12), and these messages are still being spammed into my Xorg logs.

```
[ 6794.424] (WW) AMDGPU(0): Page flip failed: Resource temporarily unavailable
[ 6794.424] (EE) AMDGPU(0): present flip failed
[ 6794.457] Failed to get FB for flip
```

A potential fix has already been merged here: https://gitlab.freedesktop.org/xorg/xserver/commit/26fe29f4fa53cbb7d51892e2cf397c084093812f?merge_request_iid=193

Fedora users already have it. I haven't tested Fedora to see if that fixes my problem.

If that fix is already in Ubuntu, I believe we're talking about a new bug.

[Timo Aaltonen (tjaalton)]

that commit is in server-1.20-branch, and eoan has a git snapshot of it which includes that commit

note that the source is not the modeset driver but 'AMDGPU', which means maybe this might help:

https://bugs.freedesktop.org/show_bug.cgi?id=110417

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.