Backlight, screen blank on suspend fixed, Thank you.
Static hostname: HpSpectre
Icon name: computer-convertible
Chassis: convertible
Machine ID: 5f5e643290004105b47bd0d046cc935f
Boot ID: a137b4546a8e40648f06a696717712c0
Operating System: Ubuntu 24.04.5 LTS
Kernel: Linux 7.0.0-31-generic
Architecture: x86-64
Hardware Vendor: HP
Hardware Model: HP Spectre x360 Convertible 13-ac0XX
Firmware Version: F.52
Firmware Date: Wed 2020-12-16
Firmware Age: 5y 9month 1d
On Fri, Aug 21, 2026 at 3:10 PM Pavol <[email protected]>
wrote:
> To fellow Ubuntu/Kubuntu users affected by this issue:
>
> As mentioned above, this bug is resolved starting with kernel version
> linux-image-7.0.0-31-generic.
>
> This fix is currently available in the `-proposed` repository for
> testing. Testing this pre-release build and providing your feedback here
> is very important for Canonical and Ubuntu developers—it helps them
> verify that the patch works reliably across different hardware
> configurations before releasing it to everyone in standard updates (and
> passing feedback upstream to the Linux kernel).
>
> If you are a regular user and run into any difficulties during the
> process, you can easily use modern AI tools (such as Gemini with
> reasoning enabled). If something goes wrong, simply copy the terminal
> output into the AI to analyze and guide you through the solution.
>
> Here is a step-by-step guide to safely install ONLY the proposed kernel
> without upgrading the rest of your system:
>
> ---
>
> ### Step 0: Check your system info (to include in your feedback comment)
> Run:
> hostnamectl
>
> ---
>
> ### Step 1: Enable the `-proposed` repository
> Open your terminal (e.g., Konsole) and run:
>
> SUITE=$(lsb_release -cs)
> sudo add-apt-repository -y "deb http://archive.ubuntu.com/ubuntu/
> ${SUITE}-proposed main restricted"
> sudo apt update
>
> ---
>
> ### Step 2: Install ONLY the new kernel from `-proposed`
> (Do NOT run `sudo apt upgrade`, as that would pull other untested system
> packages. Install only the kernel):
>
> sudo apt install -t ${SUITE}-proposed linux-image-generic linux-headers-
> generic
>
> (APT will automatically download the `...-31-generic` kernel image and
> all required modules).
>
> ---
>
> ### Step 3: Safely disable the `-proposed` repository
> Once the installation finishes, remove the proposed archive to keep your
> system stable:
>
> sudo add-apt-repository -r -y "deb http://archive.ubuntu.com/ubuntu/
> ${SUITE}-proposed main restricted"
> sudo apt update
>
> ---
>
> ### Step 4: Reboot and verify
> 1. Reboot your machine:
> sudo reboot
>
> 2. After booting, verify that you are running kernel version 31:
> uname -r
>
> ---
>
> If your brightness controls and suspend/resume are now working properly,
> please leave a comment with your hardware model (from `hostnamectl`) to
> confirm verification!
>
> --
> You received this bug notification because you are subscribed to a
> duplicate bug report (2162922).
> https://bugs.launchpad.net/bugs/2161309
>
> Title:
> Backlight regression
>
> Status in linux package in Ubuntu:
> Fix Committed
> Status in linux-hwe-7.0 package in Ubuntu:
> Fix Committed
> Status in linux source package in Noble:
> Invalid
> Status in linux-hwe-7.0 source package in Noble:
> Fix Committed
> Status in linux source package in Resolute:
> Fix Committed
> Status in linux-hwe-7.0 source package in Resolute:
> Invalid
>
> Bug description:
> -----------------------------
>
> Possible workaround until 7.0.0-31 kernel is released
> Boot with i915.enable_dpcd_backlight=0 parameter
>
> -----------------------------
>
>
> ThinkPad T480
> Intel UHD 620
> brightness works on 7.0.0-27
> brightness fails on 7.0.0-28
> /sys/class/backlight/intel_backlight changes but panel does not
>
> ProblemType: Bug
> DistroRelease: Ubuntu 26.04
> Package: linux-image-7.0.0-27-generic 7.0.0-27.27
> ProcVersionSignature: Ubuntu 7.0.0-27.27-generic 7.0.6
> Uname: Linux 7.0.0-27-generic x86_64
> ApportVersion: 2.34.0-0ubuntu2
> Architecture: amd64
> AudioDevicesInUse:
> USER PID ACCESS COMMAND
> /dev/snd/controlC0: neal 3608 F.... wireplumber
> /dev/snd/seq: neal 3589 F.... pipewire
> CasperMD5CheckResult: unknown
> CurrentDesktop: ubuntu:GNOME
> Date: Mon Jul 20 12:47:12 2026
> InstallationDate: Installed on 2026-07-12 (8 days ago)
> InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64
> (20260423.1)
> MachineType: LENOVO 20L6S6L601
> ProcFB: 0 i915drmfb
> ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-27-generic
> root=UUID=1cea3fcd-0665-4cb4-a85a-4ebc58d5aed0 ro quiet splash
> acpi_backlight=native
> crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
> SourcePackage: linux
> UpgradeStatus: No upgrade log present (probably fresh install)
> dmi.bios.date: 09/06/2025
> dmi.bios.release: 1.56
> dmi.bios.vendor: LENOVO
> dmi.bios.version: N24ET81W (1.56 )
> dmi.board.asset.tag: Not Available
> dmi.board.name: 20L6S6L601
> dmi.board.vendor: LENOVO
> dmi.board.version: SDK0J40697 WIN
> dmi.chassis.asset.tag: No Asset Information
> dmi.chassis.type: 10
> dmi.chassis.vendor: LENOVO
> dmi.chassis.version: None
> dmi.ec.firmware.release: 1.22
> dmi.modalias:
> dmi:bvnLENOVO:bvrN24ET81W(1.56):bd09/06/2025:br1.56:efr1.22:svnLENOVO:pn20L6S6L601:pvrThinkPadT480:rvnLENOVO:rn20L6S6L601:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:skuLENOVO_MT_20L6_BU_Think_FM_ThinkPadT480:pfaThinkPadT480:
> dmi.product.family: ThinkPad T480
> dmi.product.name: 20L6S6L601
> dmi.product.sku: LENOVO_MT_20L6_BU_Think_FM_ThinkPad T480
> dmi.product.version: ThinkPad T480
> dmi.sys.vendor: LENOVO
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2161309/+subscriptions
>
>
--
-Steven H. Kelty
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2161309
Title:
Backlight regression
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2161309/+subscriptions
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