Public bug reported:
== Summary ==
After the internal display is idle/locked for a while, waking it leaves ALL
displays
permanently black (internal eDP panel and external monitors). The machine is
otherwise
alive (SSH/keyboard backlight OK). The display pipe is wedged in the kernel and
only a
forced full re-modeset recovers it (toggle the external monitor off/on,
unplug/replug the
USB-C dock, or reboot). It is NOT a suspend/resume issue — no system suspend
occurs.
This is a regression: it started after the automatic HWE kernel upgrade
7.0.0-29-generic -> 7.0.0-30-generic. It never happened on 7.0.0-29.
== Impact ==
Repeatable loss of the display (multiple times per day/overnight) requiring
manual
re-plug or reboot. Renders the machine unusable after any idle/lock period.
== Hardware ==
- Laptop: HP ZBook Fury G1i 16 inch Mobile Workstation PC
- BIOS: X96 Ver. 01.02.04 (2026-01-29)
- iGPU (drives displays): Intel Arrow Lake-U [Intel Graphics] [8086:7d67],
driver i915
- dGPU: NVIDIA RTX PRO 1000 Blackwell [10de:2db8], driver 595.84, PRIME
"on-demand"
- Internal panel: AUO eDP-1, native 3840x2400@120 (pixel clock 610.10 MHz)
- External: 2x Dell P2723DE (2560x1440) via DisplayPort MST over a USB-C dock
== Software ==
- Ubuntu 24.04.4 LTS (Noble)
- Kernel: 7.0.0-30-generic (#30~24.04.1) [REGRESSION]
- Last good kernel: 7.0.0-29-generic (#29~24.04.2)
- linux-image-generic-hwe-24.04: 7.0.0-30.30~24.04.1
- xserver-xorg-core: 2:21.1.12-1ubuntu1.6 (GNOME on Xorg / gdm-x-session)
- mesa-libgallium: 25.2.8-0ubuntu0.24.04.2
- libdrm2: 2.4.125-1ubuntu0.1~24.04.2
== Steps to reproduce ==
1. Boot 7.0.0-30-generic, GNOME on Xorg, external monitors connected via USB-C
dock.
2. Lock the screen / leave the machine idle for an extended period (tens of
minutes to hours).
3. Return and press a key / move the mouse to wake the displays.
Expected: displays wake normally.
Actual: all displays stay black; the compositor is blocked (GNOME gsd-power
reports
"Error setting property 'PowerSaveMode' on org.gnome.Mutter.DisplayConfig:
Timeout").
Recovery only via: external monitor power button off/on, USB-C dock
unplug/replug, or reboot.
== Kernel error signature (verbatim, dmesg) ==
i915 0000:00:02.0: [drm] *ERROR* Timeout waiting for DDI BUF A to get active
i915 0000:00:02.0: [drm] *ERROR* Timed out waiting for DP idle patterns
i915 0000:00:02.0: [drm] *ERROR* [CRTC:150:pipe A] flip_done timed out
i915 0000:00:02.0: [drm] *ERROR* [CRTC:150:pipe A] mismatch in pixel_rate
(expected 610100, found 69416)
i915 0000:00:02.0: [drm] *ERROR* [CRTC:150:pipe A] mismatch in dpll_hw_state
i915 0000:00:02.0: [drm] *ERROR* expected: c10pll_hw_state clock: 540000 ...
i915 0000:00:02.0: [drm] *ERROR* found: c10pll_hw_state clock: 61440 ...
i915 0000:00:02.0: [drm] *ERROR* [CRTC:150:pipe A] mismatch in port_clock
(expected 540000, found 61440)
i915 0000:00:02.0: [drm] pipe state doesn't match!
WARNING: drivers/gpu/drm/i915/display/intel_modeset_verify.c:225 at
verify_crtc_state+0x51b/0x6c0 [i915], CPU#16: Xorg
RIP: 0010:verify_crtc_state+0x51e/0x6c0 [i915]
Also seen in other occurrences of the same bug:
i915 0000:00:02.0: [drm] DPLL 0: pll hw state mismatch
WARNING ... verify_single_dpll_state+0x6c7/0x7e0 [i915]
i915 0000:00:02.0: [drm] *ERROR* [CRTC:150:pipe A] DSB 1 timed out waiting for
idle
i915 0000:00:02.0: [drm] vblank wait timed out on crtc 0
== Analysis ==
On display re-enable after a low-power transition, the Arrow Lake C10/CX0 PHY
PLL is
restored to the WRONG clock (found c10pll clock 61440 / port_clock 61440 vs
expected
540000; crtc_clock 69416 vs expected 610100). As a result DDI buffer A never
activates,
DP idle-pattern/link training times out, the atomic commit hangs
(flip_done/commit-wait
timeouts), and CRTC state verification fails ("pipe state doesn't match"). The
pipe stays
wedged until a forced re-modeset (HPD event) reprograms the PLL.
== Ruled out ==
- Not system suspend/resume: no "PM: suspend" in the log; failure occurs on
plain idle wake.
- Not NVIDIA: all faults are [i915]; dGPU is on-demand and idle.
- Not PSR alone: the failure reproduced with PSR disabled
(i915_edp_psr_debug=1), so any
display power-down path (PSR, DPMS, DC power-well gating) can trigger the
same PLL-restore bug.
== Workarounds tried ==
- GNOME "screen blank = never" / disable auto-suspend: reduces one trigger,
does not fix.
- Disable PSR (i915.enable_psr=0): failure still reproduced.
- Only reliable fix: boot the previous kernel 7.0.0-29-generic (bug absent
there).
== Regression range ==
Good: 7.0.0-29-generic (#29~24.04.2)
Bad: 7.0.0-30-generic (#30~24.04.1)
Note: this problem description and issue analysis has been done with the
help of AI agent, so discrepancies might be found
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-7.0.0-30-generic 7.0.0-30.30~24.04.1
ProcVersionSignature: Ubuntu 7.0.0-30.30~24.04.1-generic 7.0.12
Uname: Linux 7.0.0-30-generic x86_64
ApportVersion: 2.28.3-0ubuntu0.1
Architecture: amd64
CRDA: N/A
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Sat Aug 29 21:25:36 2026
HibernationDevice: resume=/dev/mapper/ubuntu--vg-ubuntu--lv
resume_offset=3727360
MachineType: HP HP ZBook Fury G1i 16 inch Mobile Workstation PC
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-30-generic
root=/dev/mapper/ubuntu--vg-ubuntu--lv ro quiet splash
resume=/dev/mapper/ubuntu--vg-ubuntu--lv resume_offset=3727360 vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-7.0.0-30-generic N/A
linux-backports-modules-7.0.0-30-generic N/A
linux-firmware 20240318.git3b128b60-0ubuntu2.29
SourcePackage: linux-hwe-7.0
UpgradeStatus: No upgrade log present (probably fresh install)
WifiSyslog:
dmi.bios.date: 01/29/2026
dmi.bios.release: 2.4
dmi.bios.vendor: HP
dmi.bios.version: X96 Ver. 01.02.04
dmi.board.name: 8DE2
dmi.board.vendor: HP
dmi.board.version: KBC Version 55.38.00
dmi.chassis.type: 10
dmi.chassis.vendor: HP
dmi.ec.firmware.release: 85.56
dmi.modalias:
dmi:bvnHP:bvrX96Ver.01.02.04:bd01/29/2026:br2.4:efr85.56:svnHP:pnHPZBookFuryG1i16inchMobileWorkstationPC:pvrSBKPFV3:rvnHP:rn8DE2:rvrKBCVersion55.38.00:cvnHP:ct10:cvr:skuCP0D1EC#UUW:pfa103C_5336ANHPZBook:
dmi.product.family: 103C_5336AN HP ZBook
dmi.product.name: HP ZBook Fury G1i 16 inch Mobile Workstation PC
dmi.product.sku: CP0D1EC#UUW
dmi.product.version: SBKPFV3
dmi.sys.vendor: HP
** Affects: linux-hwe-7.0 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble
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https://bugs.launchpad.net/bugs/2165830
Title:
(Arrow Lake C10 dpll_hw_state mismatch + "DDI BUF A" timeout on eDP
resume, kernel 7.0.0‑30
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