[regression] Graphics mode does not start on Silicon Motion SM750 chip beginning with Ubuntu 18.04.3
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| xserver-xorg-video-fbdev (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
Bug Description
There is a system with the Silicon Motion SM750 graphics chip. In the kernel it supported by the sm750fb driver. Xorg server uses fbdev driver to work with it.
The graphics works on Ubuntu LTS 18.04.2, but after updating to Ubuntu 18.04.3 the fbdev driver stops detecting the device. Without output devices, the Xorg server terminates with error 1.
How to reproduce:
* Update Ubuntu 18.04.2 to version 18.04.3/18.04.4.
or
* Boot from Ubuntu Desktop livecd: 18.04.3/18.04.4 LTS, 19.04, 19.10, 20.04 LTS.
After many tests, I found:
1. This problem occurs after upgrading the Xorg server to version >= 1.20.2.
2. Building the fbdev driver from the source package "xserver-
Starting with version 1.20.2, Xorg includes a commit [1] (it is the parent for the release commit [2]) that fixes the same "regression in 0.5.0 caused by ae0aeffa" issue as the patch <revert-
[1] https:/
[2] https:/
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xserver-
ProcVersionSign
Uname: Linux 5.3.0-46-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.14
Architecture: amd64
Date: Wed Apr 29 15:32:52 2020
InstallationDate: Installed on 2020-04-28 (0 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
SourcePackage: xserver-
UpgradeStatus: No upgrade log present (probably fresh install)
| szr (iszr) wrote | #1 |
| szr (iszr) wrote | #2 |
| szr (iszr) wrote | #3 |
| szr (iszr) wrote | #4 |
| szr (iszr) wrote | #5 |
| affects: | xserver-xorg-video-fbdev-hwe-18.04 (Ubuntu) → xserver-xorg-video-fbdev (Ubuntu) |
The output of the lspci -vvnn command.