From c07fd43a5e880ec6f83b4f90e905860be52c533d Mon Sep 17 00:00:00 2001 From: PROTechThor Date: Sat, 7 Nov 2020 09:24:54 +0100 Subject: [PATCH] Move to external, edit headings --- troubleshooting/intel-igfx-troubleshooting.md | 65 +++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 troubleshooting/intel-igfx-troubleshooting.md diff --git a/troubleshooting/intel-igfx-troubleshooting.md b/troubleshooting/intel-igfx-troubleshooting.md new file mode 100644 index 0000000..75be156 --- /dev/null +++ b/troubleshooting/intel-igfx-troubleshooting.md @@ -0,0 +1,65 @@ +--- +layout: doc +title: Intel Integrated Graphics Troubleshooting +permalink: /doc/intel-igfx-troubleshooting/ +--- +# 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.preliminary_hw_support=1` option to `i915.alpha_support=1`, 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) + + +## 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 [1](#f1). + + +## Workaround for existing systems with VT-d enabled (grub / legacy mode) ## + +Edit the startup parameters for Xen: + +1. Open a terminal in dom0 +2. Edit `/etc/default/grub` (e.g. `sudo nano /etc/default/grub`) +3. Add to the line `GRUB_CMDLINE_XEN_DEFAULT` the setting `iommu=no-igfx`, save and quit +4. 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: + +1. Open a terminal in dom0 +2. Edit `/boot/efi/EFI/qubes/xen.cfg` (e.g. `sudo nano /boot/efi/EFI/qubes/xen.cfg`) +3. Add to the line `options` the setting `iommu=no-igfx`, save and quit + +1 [↩](#a1-1) +