Public bug reported:

Hardware: Lenovo ThinkPad P1 Gen 7 (21KV001EUS)
GPU: Intel Meteor Lake-P [Arc Graphics] 8086:7d55 rev 08, i915, DISPLAY_VER 14 
stepping C0
Also present: NVIDIA 580.173.02 open module (hybrid); bug reproduces for others 
with NVIDIA disabled
Kernel: 7.0.0-30-generic (7.0.12), Kubuntu 26.04
BIOS: N48ET35W (1.22), 2026-06-23
Session: KDE Plasma / kwin_wayland
Boot cmdline already includes: i915.enable_psr=0 i915.enable_dc=0

SYMPTOM
On resume from s2idle after a ~34.5 hour dwell, the internal panel never
comes back. The kernel stays alive (SSH works); only the display is dead.
State does not recover across subsequent suspend/resume cycles — a later
resume fails identically with "PHY A failed to change powerdown state".
Reboot required.

FIRST FAILURE (resume at 09:11:59)
  *ERROR* Failed to bring PHY A to idle.
  *ERROR* PHY A Read 0c70 failed after 3 retries.
  *ERROR* PHY A Write 0c70 failed after 3 retries.

Both reads and writes to the C10 PHY message bus fail, so the PLL is never
programmed. Readback shows an unprogrammed PLL:
  port_clock  expected 540000, found 61440   (multiplier 140 -> 16)
  pixel_rate  expected 572010, found 65082
Everything downstream follows: DDI BUF A timeout, DP idle-pattern timeout,
verify_crtc_state WARN in intel_display_driver_resume, then continuous
flip_done / commit wait / DSB timeouts from the compositor.

TRIGGER NOTES
Every suspend cycle in this log shows the pattern:
  PM: suspend entry (s2idle)
  PM: Some devices failed to suspend, or early wake event detected
  PM: suspend exit
  PM: suspend entry (s2idle)   <- the real one
This double-entry also appears in LP #2150605. mem_sleep offers only
[s2idle]; this firmware provides no S3, and /sys/power/state lacks 'disk'.

RULED OUT
- i915.enable_psr=0 and i915.enable_dc=0: already set, no effect
- NVIDIA: other reporters reproduce with the dGPU disabled
- xe.force_probe: per LP #2150605, binds but hits an engine-reset storm

KNOWN GOOD
Multiple reporters, including two on P1 Gen 7 and P1 Gen 8, confirm 6.19.14
is unaffected. This is a 7.0-series regression. Mainline is not a viable
daily workaround here due to lack of security updates.

REFERENCES
- LP #2150605 (Arrow Lake-S, same signature, different platform)
- https://bbs.archlinux.org/viewtopic.php?id=313469
- drm/i915 work items #16098 and #16042
- Possible fix upstream: afe3f7471623 (v7.1-rc1), unconfirmed

ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-30-generic 7.0.0-30.30
ProcVersionSignature: Ubuntu 7.0.0-30.30-generic 7.0.12
Uname: Linux 7.0.0-30-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Wed Aug 26 12:48:05 2026
InstallationDate: Installed on 2025-08-25 (366 days ago)
InstallationMedia: Kubuntu 25.04 "Plucky Puffin" - Release amd64 (20250417)
IwDevWlp9s0f0Link: Not connected.
MachineType: LENOVO 21KV001EUS
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-30-generic 
root=UUID=8fa33305-d5e7-4a92-9483-f7af9f1333de ro quiet 
rd.luks.uuid=d6b3f1f2-6103-43fe-b2c1-c1dcea446d91 splash i915.enable_psr=0 
i915.enable_dc=0
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No 
PulseAudio daemon running, or not running as session daemon.
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-05-19 (99 days ago)
dmi.bios.date: 06/23/2026
dmi.bios.release: 1.22
dmi.bios.vendor: LENOVO
dmi.bios.version: N48ET35W (1.22 )
dmi.board.asset.tag: Not Available
dmi.board.name: 21KV001EUS
dmi.board.vendor: LENOVO
dmi.board.version: SDK0T76528 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.ec.firmware.release: 1.15
dmi.modalias: 
dmi:bvnLENOVO:bvrN48ET35W(1.22):bd06/23/2026:br1.22:efr1.15:svnLENOVO:pn21KV001EUS:pvrThinkPadP1Gen7:rvnLENOVO:rn21KV001EUS:rvrSDK0T76528WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_21KV_BU_Think_FM_ThinkPadP1Gen7:pfaThinkPadP1Gen7:
dmi.product.family: ThinkPad P1 Gen 7
dmi.product.name: 21KV001EUS
dmi.product.sku: LENOVO_MT_21KV_BU_Think_FM_ThinkPad P1 Gen 7
dmi.product.version: ThinkPad P1 Gen 7
dmi.sys.vendor: LENOVO

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug resolute wayland-session

** Attachment added: "i915-phy-a-resume.log"
   
https://bugs.launchpad.net/bugs/2165164/+attachment/5995603/+files/i915-phy-a-resume.log

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https://bugs.launchpad.net/bugs/2165164

Title:
  i915 Meteor Lake (ThinkPad P1 Gen 7): PHY A message bus unresponsive
  on resume from long s2idle dwell — C10 PLL left unprogrammed, display
  unrecoverable

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