Public bug reported:
On the ASUS Vivobook S 15 (Snapdragon X / X1E-78-100), when the internal eDP
panel is powered off by the screensaver (DRM DPMS off) and then woken up, only
half of the panel displays content — the other half stays black. The session
keeps running normally; only the panel output is broken.
A full display re-initialization restores the panel completely:
- Switch to a text VT (Ctrl+Alt+F3) and back (Ctrl+Alt+F2), or
- `chvt 3 && chvt <previous>` from a root shell
After the VT switch the panel is fully functional again — no reboot or logout
needed. This proves the failure is in the display pipeline's power-on path
(encoder/panel re-init after DPMS), not in the userspace session.
Affected hardware / software
----------------------------
- ASUS Vivobook S 15 S5507QA (Snapdragon X X1E-78-100), internal eDP panel
Samsung ATNA33XC20 (driver: panel_samsung_atna33xc20)
- Display controller: msm_dpu ae01000.display-controller (drm/msm, DPU 9.0.2:
"dpu hardware revision:0x90020000")
- Ubuntu 26.04.1 "Resolute", arm64
- Kernel: 7.0.0-30-generic (latest at time of report, resolute-updates)
- GNOME Shell on Wayland
Reproduction
------------
1. Boot normally, log in (Wayland session)
2. Let the screensaver blank the panel (GNOME Screen Blank / DPMS power-off)
3. Wake the display (keypad/touch)
4. Only half of the panel shows output; the other half remains black
5. Ctrl+Alt+F3 / Ctrl+Alt+F2 → panel fully restored
Notes / observations
--------------------
- No drm/dpu error messages are logged at the moment the half-screen state
appears — the failure is silent (journalctl -k shows only the boot-time
"dpu hardware revision:0x90020000" line).
- Unrelated-but-possibly-relevant error seen earlier this boot under heavy
software-rendering load:
[drm:dpu_crtc_frame_event_cb [msm]] *ERROR* crtc109 event 1 overflow
(observed while the GPU was unaccelerated due to missing firmware — see
separate linux-firmware report; the half-screen issue persists
independently of GPU acceleration state.)
- The panel is driven with DSC; a plausible cause is incorrect DSC/tile
reconfiguration on the DPMS power-up path in dpu1 encoder code, since a
full modeset (VT switch) reprograms everything and recovers.
- Not the same as the known x1e80100 eDP HPD pinctrl issue (Stephan Gerhold's
Aug 2025 series, display never comes up at all) — here the display works
fine from boot and only breaks on DPMS resume.
Suggested next steps for maintainers
------------------------------------
- Reproduce with dpms off/on (e.g. `sleep 5 &&swaymsg ...` equivalent:
`modetest -M msm_dpu -w` DPMS cycles, or GNOME screen-blank timer)
- Instrument dpu1 encoder enable/power-on path around DSC config restore
- Compare against the DPMS handling for the same panel on other x1e80100
devices (Lenovo T14s Gen 6 uses the same ATNA33XC20 panel and may be
affected identically)
Environment (from affected machine)
-----------------------------------
DistroRelease: Ubuntu 26.04
Architecture: arm64
MachineType: ASUSTeK COMPUTER INC. Vivobook S 15 S5507QA_S5507QAD
Kernel: 7.0.0-30-generic
SourcePackage: linux (version 7.0.0-30.30)
Tags: arm64 wayland-session kernel-daily-bug
Happy to test patches, capture mode dumps (modetest), or edid on
request.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/2165828
Title:
ASUS Vivobook S 15 (x1e80100, Samsung ATNA33XC20 eDP): only half of
internal panel displays after DPMS off/on; VT switch (full modeset)
recovers
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