Public bug reported:
Fresh install of Ubuntu 26.04 on an LG Gram 17 (17Z90U-family) laptop.
The built-in eDP panel shows total scanout corruption under the xe
driver: the screen fills with unreadable ~1-2px horizontal line
striping. This affects graphical sessions AND text VTs - switching with
Ctrl-Alt-F1/F3 changes the screen but no VT is ever readable - so the
corruption is at the kernel display layer, below userspace.
The only way to get a usable display is booting with nomodeset, which
disables the xe modeset and falls back to the firmware framebuffer
(low-res, no acceleration).
Hardware:
- Laptop: LG Gram 17 (17Z90U-family)
- iGPU: Intel Panther Lake [8086:b0a0], display IP version 30.00
stepping B0 (xe3lpd) - drives the panel
- dGPU: NVIDIA RTX 5050 Mobile [10de:2d98] - present but irrelevant,
panel is on the Intel iGPU
Kernel error signature (from journalctl -b -k):
xe 0000:00:02.0: [drm] *ERROR* CPU pipe A FIFO underrun
xe 0000:00:02.0: [drm] Selective fetch area calculation failed in pipe A
(the second line appears only when PSR is enabled)
Reproduced on every kernel available to me:
- 7.0.0-22-generic (Ubuntu archive)
- 7.0.0-1005-oem (linux-oem-26.04)
- 7.0.11-070011-generic (Ubuntu mainline build)
Workarounds tried that did NOT fix it:
- xe.enable_psr=0
- xe.enable_fbc=0
- xe.enable_psr=0 xe.enable_fbc=0 (combined)
- modprobe.blacklist=nouveau (confirmed unrelated - nouveau does not
hang boot; striping is identical with or without it)
Only nomodeset produces a usable display.
Steps to reproduce:
1. Boot Ubuntu 26.04 on this hardware without nomodeset
2. xe driver loads and modesets the eDP panel
3. Panel scanout is corrupted into unreadable striping; no VT readable
Expected: panel displays normally under the xe driver.
Actual: total scanout corruption; only nomodeset is usable.
I can do further testing if needed (I have the hardware at hand)
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-1005-oem 7.0.0-1005.5
ProcVersionSignature: Ubuntu 7.0.0-1005.5-oem 7.0.2
Uname: Linux 7.0.0-1005-oem x86_64
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Thu Jun 4 17:27:32 2026
InstallationDate: Installed on 2026-06-03 (1 days ago)
InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423.1)
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
SourcePackage: linux-signed-oem-7.0
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: linux-signed-oem-7.0 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2155307
Title:
[LG Gram 17Z90U] xe: CPU pipe A FIFO underrun corrupts Panther Lake
eDP panel - only nomodeset works
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