*** This bug is a duplicate of bug 2161309 ***
https://bugs.launchpad.net/bugs/2161309
Public bug reported:
# Bug Report: [Regression][i915] Black screen on resume from S3 suspend
on Haswell (assert_can_disable_lcpll warning)
## Title
[Regression][i915] Black screen on resume from S3 suspend on Haswell
(assert_can_disable_lcpll warning)
## Description
### Summary
On an ASUS N56JN laptop (Intel Haswell Core i7-4710HQ / HD Graphics 4600),
waking from S3 suspend results in a completely black/unpowered internal eDP
display on kernel 7.0.0-28-generic.
The issue does not occur on kernel 6.17.0-14-generic, where S3 suspend
and display resume work reliably.
### Kernel Warning Trace
During i915_pm_suspend_late on 7.0.0-28-generic, the kernel emits the following
warning:
i915 0000:00:02.0: [drm] CPU PWM1 enabled
WARNING: drivers/gpu/drm/i915/display/intel_display_power.c:1225 at
assert_can_disable_lcpll+0x70e/0x880 [i915]
i915 0000:00:02.0: [drm] PCH PWM1 enabled
WARNING: drivers/gpu/drm/i915/display/intel_display_power.c:1232 at
assert_can_disable_lcpll+0x770/0x880 [i915]
RIP: assert_can_disable_lcpll
Call Trace:
hsw_disable_lcpll
hsw_enable_pc8
intel_display_power_suspend_late
i915_drm_suspend_late
i915_pm_suspend_late
### Steps to Reproduce
1. Boot kernel 7.0.0-28-generic.
2. Trigger S3 sleep (systemctl suspend or via desktop menu).
3. Wake the system.
### Expected Result
System resumes and internal eDP panel powers on.
### Actual Result
System wakes (network/audio active), but the internal screen panel remains
unpowered/black.
### Hardware Details
- Laptop: ASUS N56JN
- CPU: Intel Core i7-4710HQ (Haswell)
- Integrated GPU: Intel HD Graphics 4600 (i915 driver)
- Discrete GPU: NVIDIA GeForce 840M
- Working Kernel: 6.17.0-14-generic
- Broken Kernel: 7.0.0-28-generic
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-6.17.0-14-generic 6.17.0-14.14~24.04.1
ProcVersionSignature: Ubuntu 6.17.0-14.14~24.04.1-generic 6.17.9
Uname: Linux 6.17.0-14-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.28.3-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: stefano 2826 F.... wireplumber
/dev/snd/controlC1: stefano 2826 F.... wireplumber
/dev/snd/seq: stefano 2822 F.... pipewire
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Wed Aug 26 17:33:54 2026
InstallationDate: Installed on 2025-05-25 (458 days ago)
InstallationMedia: Ubuntu 24.04.2 LTS "Noble Numbat" - Release amd64 (20250215)
MachineType: ASUSTeK COMPUTER INC. N56JN
ProcEnviron:
LANG=it_IT.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.17.0-14-generic
root=UUID=b19a6e2b-f6b5-442f-8ea8-18e7811de6d6 ro quiet splash
mem_sleep_default=deep acpi_osi= acpi_backlight=native vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-6.17.0-14-generic N/A
linux-backports-modules-6.17.0-14-generic N/A
linux-firmware 20240318.git3b128b60-0ubuntu2.27
SourcePackage: linux-hwe-6.17
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/12/2014
dmi.bios.release: 4.6
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: N56JN.203
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: N56JN
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvrN56JN.203:bd05/12/2014:br4.6:svnASUSTeKCOMPUTERINC.:pnN56JN:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnN56JN:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:skuASUS-NotebookSKU:
dmi.product.family: N
dmi.product.name: N56JN
dmi.product.sku: ASUS-NotebookSKU
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.
** Affects: linux-hwe-7.0 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
** Package changed: linux-hwe-6.17 (Ubuntu) => linux-hwe-7.0 (Ubuntu)
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https://bugs.launchpad.net/bugs/2165156
Title:
[Regression][i915] Black screen on resume from S3 suspend on Haswell
(assert_can_disable_lcpll warning)
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