Pixelbook Go (ATLAS) 4K – i915 “CPU pipe A FIFO underrun”
I’m trying to get omarchy loaded onto my 2019 Google Pixelbook Go. When omarchy display didn’t work, I tried switching to arch - same issue.
Problem
Firmware/bootloader output is fine, but as soon as i915 loads the internal display
flashes several times and then shows a few faint horizontal lines (or stays black).
Booting with nomodeset works (simpledrm). Same behavior from the Omarchy ISO,
the Arch ISO, and the installed system.
System Details
- Device: Google Pixelbook Go (ATLAS), i7-8500Y, 16GB, 4K panel
- Firmware: Full ROM / UEFI – tested MrChromebox-2609.3 and 2606.1 (same result)
- OS: Arch Linux, kernel 7.2.15-arch1-1 and linux-lts (same result)
- Bootloader: Limine
Kernel log on every failed boot:
i915 0000:00:02.0: [drm] ERROR CPU pipe A FIFO underrun
From a drm.debug=0x1e log:
- Firmware leaves eDP-1 at 1920x1080 with PCH pfit scaling to 3840x2160 (BIOS fb not reused)
- i915 does a full modeset to native 3840x2160 @ 533300 kHz, 4 lanes @ 432000
(1599900 / 1728000 link bandwidth) - FBC is enabled on plane 1A, then the FIFO underrun, then “Disabling FBC due to FIFO underrun”
- SAGV is enabled after the plane update
- No link-training errors
Kernel parameters tried (none but nomodeset helped):
- nomodeset prevents the issue (but also prevents me from using omarchy/hyprland)
- i915.enable_psr=0
- i915.enable_psr=0 i915.enable_fbc=0 i915.enable_dc=0
- …plus intel_idle.max_cstate=2, and intel_idle.max_cstate=1 alone
- i915.fastboot=0 i915.enable_psr=0
- video=eDP-1:1920x1080
- video=eDP-1:1920x1080@60 i915.enable_fbc=0 i915.enable_psr=0 (black screen instead of
flashing, but the underrun is still logged)
Full debug log (i915/drm lines): https://termbin.com/0i7me
Is this a known issue with the 4K ATLAS panel, and is there a firmware-side or
kernel-side fix or workaround? Happy to test builds or provide more logs.