[Bug 2161214] Re: [Regression] Black screen / no backlight on resume from suspend in kernel 7.0.0-28-generic (Dell Precision M4800, Optimus Intel + Quadro K1100M on nouveau)

INTRODUCTION AND FOCUS OF THE BUG REPORT (BUG REPORT, LINUX KERNEL, KUBUNTU) First, a quick note for the AI to ensure this transcription is correct: this is a bug report regarding the Linux kernel on Kubuntu. Now, I will proceed to the report itself. Dear developers, I would be very grateful if you could fix this bug. I realize that my computer is very, very old. That is one thing, but on the other hand, Linux distributions are generally designed to support older hardware as well. Therefore, I hope you will be willing to resolve this issue. NON-STANDARD SYSTEM SETTINGS AND SECURITY (FSCRYPT, SYSTEMD-HOMED, FINGERPRINT) It is true that I have a slightly non-standard setup on Kubuntu. I have an encrypted home directory using fscrypt, and I also use systemd-homed with fingerprint authentication to unlock the computer and the login screen. It is actually fortunate that I use this option—these fingerprints—because it made it much easier to identify the bug and pinpoint where the error stems from. I can assure you with absolute certainty, indeed with 100% confidence, that this is related to the Linux kernel, specifically something in the graphics department, most likely the graphics drivers. BUG BEHAVIOR AND SYMPTOMS (BRIGHTNESS REGULATION, BLACK SCREEN, SLEEP MODE, FIDO2) It is important to supplement this bug report with additional information: whenever the very latest version of the Linux kernel is installed, it is accompanied by other symptoms. Specifically, I am unable to regulate the screen brightness; it is permanently stuck, I believe, at the absolute lowest brightness level. Furthermore, as soon as I suspend the computer and wake it back up, the screen is 100% black, as if the computer were completely turned off and fails to turn on at all. We can reliably identify this as a graphics-related issue because, by looking at the flashing of the FIDO2 security key, it is possible to deduce and conclude that I have successfully logged in. There are LEDs on it that clearly signal when a successful login has occurred. Thus, everything was working completely fine, except for the single fact that the screen remained black the entire time. THANKS TO THE DEVELOPERS AND CONCLUSION (BUG FIX, SUPPORT, THANKS) So, dear developers, I wish you success in fixing this. May it cost you as little work as possible, bring a great benefit, and may you manage to fix it as quickly as possible with minimal effort. That is my wish for you. I wish you the best of luck and thank you, developers, for your hard work. Additionally, as a piece of supplementary information, I personally believe that slightly non-standard configurations, such as home directory encryption via systemd-homed, should not play a large or significant role in this issue. -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2161214 Title: [Regression] Black screen / no backlight on resume from suspend in kernel 7.0.0-28-generic (Dell Precision M4800, Optimus Intel + Quadro K1100M on nouveau) Status in linux package in Ubuntu: New Bug description: Hi, I am experiencing a regression in the latest Ubuntu kernel package. **Hardware & GPU details:** - Laptop: Dell Precision M4800 - iGPU: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller - dGPU: NVIDIA Corporation GK107GLM [Quadro K1100M] (rev a1) - Driver in use: 'nouveau' (open-source kernel driver) - OS: Kubuntu 26.04 (Wayland) **Symptoms:** When waking up the laptop from suspend, the screen remains pitch black (no backlight turns on). The system is actually responsive in the background: when I press my FIDO2 security key, it blinks, I can authenticate and the system unlocks, but the display output/backlight remains completely dead. **Regression confirmation:** - Kernel 7.0.0-28-generic: BROKEN (reproducible every time on resume, black screen) - Kernel 7.0.0-27-generic: OK (works perfectly, screen wakes up immediately on resume) Since only the kernel version was changed and Mesa/KWin remained the same, this is a clear kernel regression in the DRM/nouveau/i915 subsystem. ProblemType: Bug DistroRelease: Ubuntu 26.04 Package: linux-image-7.0.0-28-generic 7.0.0-28.28 ProcVersionSignature: Ubuntu 7.0.0-28.28-generic 7.0.12 Uname: Linux 7.0.0-28-generic x86_64 ApportVersion: 2.34.0-0ubuntu2 Architecture: amd64 CasperMD5CheckResult: unknown CurrentDesktop: KDE Date: Sat Jul 18 22:38:20 2026 InstallationDate: Installed on 2026-04-28 (81 days ago) InstallationMedia: Kubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423) IwDevWlp3s0Link: Not connected. MachineType: Dell Inc. Precision M4800 ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-28-generic root=UUID=0865911a-d995-4fff-b0d8-34f3e26f1603 ro quiet splash PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon. SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) WifiSyslog: dmi.bios.date: 10/08/2018 dmi.bios.release: 65.25 dmi.bios.vendor: Dell Inc. dmi.bios.version: A25 dmi.board.name: 0V5GVY dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA25:bd10/08/2018:br65.25:svnDellInc.:pnPrecisionM4800:pvr00:rvnDellInc.:rn0V5GVY:rvrA00:cvnDellInc.:ct9:cvr:sku05CC:pfa: dmi.product.name: Precision M4800 dmi.product.sku: 05CC dmi.product.version: 00 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2161214/+subscriptions