I've sent up the fixes for xorg to stonking and also uploaded to unapproved for noble and resolute.
The packages are available here on this PPA for early testing. https://launchpad.net/~superm1/+archive/ubuntu/lp2136140/+packages ** Description changed: - Since Kernel 6.18, there is a new "boot_display" attribute for display - drivers that do not represent VGA compatible devices: - https://lore.kernel.org/linux- - pci/[email protected]/T/#t + [ Impact ] - This attribute essentially replaces the "boot_vga" attribute that was - used by user space applications to determine which is the primary GPU on - a system. This is no longer accurate, e. g. for devices with recent AMD - iGPUs, because they don't appear as VGA compatible devices. + * Since Kernel 6.18, there is a new "boot_display" attribute for display + drivers that do not represent VGA compatible devices: + https://lore.kernel.org/linux-pci/[email protected]/T/#t - Unfortunately, sticking to the old attribute can lead to an incorrect - choice of primary GPU, resulting in user space being unable to render. - However, current versions of the xserver still don't honor the new - "boot_display" attribute, making some devices unusable with X unless you - modify the config to select another primary GPU. + * This attribute replaces the "boot_vga" attribute that was used by user + space applications to determine which is the primary GPU on a system. + The old attribute is no longer accurate for devices with recent AMD iGPUs, + because they don't appear as VGA compatible devices. - There are already patches for Xorg, but they haven't been merged and honestly, the entire X-project appears quite dead. - Therefore, it would be great to merge the patches at least into the Ubuntu packages: + * Sticking to the old "boot_vga" attribute leads to an incorrect choice of + primary GPU, resulting in user space being unable to render on systems + with modern AMD iGPUs. - - https://gitlab.freedesktop.org/xorg/lib/libpciaccess/-/merge_requests/39 - - https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2038 + * Current versions of xserver don't honor the new "boot_display" attribute, + making some devices unusable with X unless users manually modify the + config to select another primary GPU. + + * The fix requires backporting upstream patches from the xorg project: + - https://gitlab.freedesktop.org/xorg/lib/libpciaccess/-/merge_requests/39 + - https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2038 + + [ Test Plan ] + + * On a system with a recent AMD iGPU (where the iGPU does not appear + as a VGA compatible device): + + * Without the fix: + 1. Install current xserver package + 2. Boot the system with default X configuration + 3. Observe that X fails to render or selects the wrong GPU + 4. Verify that /sys/class/drm/card*/device/boot_display exists but + is not being used by X + + * With the fix: + 1. Install updated xserver and libpciaccess packages + 2. Boot the system with default X configuration + 3. Verify that X correctly identifies and uses the primary GPU + indicated by the boot_display attribute + 4. Confirm that rendering works correctly without manual configuration + + * Test on systems with: + - Traditional VGA-compatible GPUs (should continue to work via boot_vga) + - Modern AMD iGPUs (should work via new boot_display attribute) + - Hybrid graphics systems with multiple GPUs + + [ Where problems could occur ] + + * The changes modify GPU detection logic in libpciaccess and xserver. + If the boot_display attribute is incorrectly parsed or prioritized, + the wrong GPU could be selected as primary on some systems. + + * On systems where both boot_vga and boot_display attributes exist, + there could be conflicts in precedence that result in unexpected + GPU selection. + + * The changes affect core X server initialization, so bugs could + manifest as complete X startup failures, not just incorrect GPU + selection. + + * Multi-GPU systems (especially those with discrete + integrated + graphics) could be affected if the boot_display detection logic + doesn't handle all configuration permutations correctly. + + [ Other Info ] + + * Upstream patches merged. + + * Kernel patches are already in Ubuntu now. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2136140 Title: Add support for "boot_display" attribute To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-drivers-common/+bug/2136140/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
