5.1 KiB
Intel Integrated Graphics Troubleshooting
Software Rendering or Video Lags
If you are experiencing this issue, you will see extremely slow graphics
updates. You will be able to watch the screen and elements paint slowly from
top to bottom. You can confirm this is the issue by looking for a line similar
to the following in your /var/log/Xorg.0.log
file:
[ 131.769] (EE) AIGLX: reverting to software rendering
Newer versions of the Linux kernel have renamed the i915.alpha_support=1
option (which was originally called i915.preliminary_hw_support=1
) to
i915.force_probe=*
, so if you needed this kernel option in the past you will
have to rename it or add it to your configuration files (follow either GRUB2 or
EFI, not both):
-
GRUB2:
/etc/default/grub
,GRUB_CMDLINE_LINUX
line and Rebuild grub config (grub2-mkconfig -o /boot/grub2/grub.cfg
) -
EFI:
/boot/efi/EFI/qubes/xen.cfg
,kernel=
line(s)
If you are unsure as to which parameter works with your kernel, check whether your kernel log from your latest boot has a message containing "i915: unknown parameter".
Fix tearing (glitches/artifacts/corruption/...)
By default Qubes OS uses fbdev
, the framebuffer/modesetting driver. Without
compositing VM windows exhibit graphical artefacts (dom0 is unaffected).
Workarounds:
-
enable compositing; it is enabled by default in XFCE (if it was disabled for some reason, re-enabling it is done in "Window Manager Tweaks"; restarting
xfwm
isn't necessary).i3wm
,AwesomeWM
orDWM
window managers don't provide compositing so their users would have to install a standalone compositing manager (the old faq mentions usingcompton
butpicom
is a more recent fork. Both are packaged in Fedora 32 and can be installed easily withqubes-dom0-update
). -
or switch to the
intel
driver. Note: for some users theintel
driver is unstable, triggering crashes/reboots ! - either reproducible (eg. moving a floating window to another monitor when usingi3wm
) to random and infrequent (eg. 1-3x a day with XFCE). In that case using the "UXA" acceleration method instead of the default "SNA" method seems to fix some crashes but may introduce other crashes. PSR (Panel Self Refresh) may also cause tearing issues; it can be disabled globally in GRUB2/EFI with thei915.enable_psr=0
boot option.Create
/etc/X11/xorg.conf.d/20-intel.conf
with the following content:Section "Device" Identifier "Intel Graphics" Driver "Intel" # UXA is more stable than the default SNA for some users Option "AccelMethod" "UXA" EndSection
A logout/login is then required.
Finding out which of intel
or fbdev
driver is in use:
-
grep -E 'LoadModule.*(fbdev|intel)"' /var/log/Xorg.0.log
; eg. forintel
:(II) LoadModule: "intel"
-
or,
sudo lsof +D /usr/lib64/xorg/modules/drivers/
; eg. forfbdev
:Xorg [...] /usr/lib64/xorg/modules/drivers/modesetting_drv.so
IOMMU-related issues
Dom0 Kernels currently included in Qubes have issues related to VT-d (IOMMU) and some versions of the integrated Intel Graphics Chip. Depending on the specific hardware / software combination the issues are quite wide ranging, from apparently harmless log errors, to VM window refresh issues, to complete screen corruption and crashes rendering the machine unusable with Qubes.
Such issues have been reported on at least the following machines:
- HP Elitebook 2540p
- Lenovo x201
- Lenovo x220
- Thinkpad T410
- Thinkpad T450s
Log errors only on :
- Librem 13v1
- Librem 15v2
The installer for Qubes 4.0 final has been updated to disable IOMMU for the integrated intel graphics by default. However, users of 3.2 may experience issues on install or on kernel upgrades to versions higher than 3.18.x.
Disabling IOMMU for the integrated graphics chip is not a security issue, as the device currently lives in dom0 and is not passed to a VM. This behaviour is planned to be changed as of Qubes 4.1, when passthrough capabilities will be required for the GUI domain.
Workaround for existing systems with VT-d enabled (grub / legacy mode)
Edit the startup parameters for Xen:
- Open a terminal in dom0
- Edit
/etc/default/grub
(e.g.sudo nano /etc/default/grub
) - Add to the line
GRUB_CMDLINE_XEN_DEFAULT
the settingiommu=no-igfx
, save and quit - Commit the change with
sudo grub2-mkconfig --output /boot/grub2/grub.cfg
Workaround for existing systems with VT-d enabled (UEFI)
Edit the startup parameters for Xen:
- Open a terminal in dom0
- Edit
/boot/efi/EFI/qubes/xen.cfg
(e.g.sudo nano /boot/efi/EFI/qubes/xen.cfg
) - Add to the line
options
the settingiommu=no-igfx
, save and quit