Public bug reported:
Hardware: Dell laptop, Intel Core Ultra (Meteor Lake, device ID 7d45), internal
eDP panel
Symptom: on kernel 7.0.0-28-generic, internal panel brightness is stuck
near-minimum regardless of slider/brightnessctl value; external monitor
unaffected
Kernel 7.0.0-27-generic works correctly with i915.invert_brightness=0
Neither i915.invert_brightness=1, acpi_backlight=native/vendor, nor
i915.enable_dpcd_backlight=0/1 fixed it on -28
This looks like a regression specific to -28's i915 backlight/PWM handling for
this panel
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-28-generic 7.0.0-28.28
ProcVersionSignature: Ubuntu 7.0.0-27.27-generic 7.0.6
Uname: Linux 7.0.0-27-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: razor 5976 F.... wireplumber
/dev/snd/controlC1: razor 5976 F.... wireplumber
/dev/snd/seq: razor 5954 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sat Jul 25 21:48:58 2026
InstallationDate: Installed on 2026-01-29 (177 days ago)
InstallationMedia: Ubuntu 24.04.3 LTS "Noble Numbat" - Release amd64
(20250805.1)
MachineType: Dell Inc. Latitude 5450
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-27-generic
root=UUID=b12f378b-8146-4c1e-bdac-56b046c47797 ro quiet splash
i915.invert_brightness=0
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-07-03 (22 days ago)
dmi.bios.date: 12/22/2025
dmi.bios.release: 1.20
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.20.1
dmi.board.name: 00Y01Y
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.ec.firmware.release: 1.20
dmi.modalias:
dmi:bvnDellInc.:bvr1.20.1:bd12/22/2025:br1.20:efr1.20:svnDellInc.:pnLatitude5450:pvr:rvnDellInc.:rn00Y01Y:rvrA00:cvnDellInc.:ct10:cvr:sku0CB2:pfaLatitude:
dmi.product.family: Latitude
dmi.product.name: Latitude 5450
dmi.product.sku: 0CB2
dmi.sys.vendor: Dell Inc.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2161809
Title:
kernel 7.0.0-28-generic brightness bug
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