[Impact]
* IGLX is a way for an opengl application sending the 3D drawing GLX commands to the Xorg server for rendering instead of using the DRI infrastructure it is commonplace for High Performance Compute and Scientific institutions to use this feature of the Xorg server. (ref: https://www.phoronix.com/scan.php?page=news_item&px=Xorg-IGLX-Potential-Bye-Bye)
* The feature is completely broken, currently, and any attempt to use it will cause the Xorg server to crash. This feature has been broken since a commit upstream in 2016.
* The attached patch is from the revert commit entered into the upstream repository on 28 Jan 2020 following a git bisect of the bug discovering the offending commit.
[Test Case]
* Create a new file at /etc/X11/xorg.conf.d/99-IGLX.conf with the following contents:
```
Section "ServerFlags"
Option "IndirectGLX" "on"
EndSection
```
* Log out of your Xorg session
* Switch to a VT (Ctrl+Alt+F2) and login
* Run `sudo systemctl restart gdm` to restart Xorg
* Login to the graphical session
* If you do not have mesa-utils installed, then install it with the terminal command `sudo apt install mesa-utils`
* Open a terminal and execute `LIBGL_ALWAYS_INDIRECT=1 glxgears`
* If the fix is successful then glxgears should start and remain active without the Xorg server or glxgears crashing/segfaulting
[Regression Potential]
* This change is within DRI-related functionality and so might break all 3D accelerated applications.
* There is a potential that the change is insufficient to fix the IGLX feature and so attempts to use it may still have undesirable and undefined results.
* Upstream has run the patch through their CI system, which passed with no errors. This does not necessarily mean the patch will achieve the desired results, but at least indicates that the code does compile cleanly and can start an Xvfb headless instance.
[Other Info]
* This bug affects Ubuntu releases all the way back to, and including, Bionic 18.04.
---- Original Bug Report Follows ----
There's already an upstream bug report here:
https://bugs.freedesktop.org/show_bug.cgi?id=99555
Basically, with Option "IndirectGLX" "True" and LIBGL_ALWAYS_INDIRECT=1 I get immediate crashes e.g. with glxgear:
steved@xubuntu:~$ LIBGL_ALWAYS_INDIRECT=true glxgears
Running synchronized to the vertical refresh. The framerate should be
approximately the same as the monitor refresh rate.
X Error of failed request: 255
Major opcode of failed request: 155 (GLX)
Minor opcode of failed request: 1 (X_GLXRender)
Serial number of failed request: 42
Current serial number in output stream: 936
I am trying to run what is effectively a traditional X Terminal, but as the hardware I am using has a 3D accelerated chipset it seems sensible to try to use it..
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xserver-xorg-core 2:1.19.6-1ubuntu4
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Uname: Linux 4.15.0-22-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.1
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
Date: Tue Jun 12 10:09:30 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
DkmsStatus:
rtl8812au, 4.3.8.12175.20140902+dfsg, 4.15.0-22-generic, x86_64: installed
rtl8812au, 4.3.8.12175.20140902+dfsg, 4.15.0-23-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
Intel Corporation Device [8086:5a85] (rev 0b) (prog-if 00 [VGA controller])
Subsystem: Intel Corporation Device [8086:2212]
InstallationDate: Installed on 2018-05-31 (11 days ago)
InstallationMedia: Xubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
MachineType: AZW S I
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_GB.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-22-generic root=/dev/mapper/xubuntu--vg-root ro noresume
SourcePackage: xorg-server
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/18/2017
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 00.12
dmi.board.asset.tag: Default string
dmi.board.name: AB1
dmi.board.vendor: IP3 Tech
dmi.board.version: Default string
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 35
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr00.12:bd12/18/2017:svnAZW:pnSI:pvrDefaultstring:rvnIP3Tech:rnAB1:rvrDefaultstring:cvnDefaultstring:ct35:cvrDefaultstring:
dmi.product.family: Mini PC
dmi.product.name: S I
dmi.product.version: Default string
dmi.sys.vendor: AZW
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.91-2
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.0~rc5-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.0~rc5-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu4
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2
LIBGL_ALWAYS_
fails on latest git on r600 with:
X Error of failed request: 255
Major opcode of failed request: 155 (GLX)
Minor opcode of failed request: 1 (X_GLXRender)
Serial number of failed request: 42
Current serial number in output stream: 164
After rendering one frame. this is on a ATI HD5850. This is 100% repeatable and occures with every opengl app. Direct Rendering works fine.
Indirect rendering works with the vesa x11 driver and llvmpipe. xf86-video-ati versus xf86-video-