Same issue on Lenovo ThinkPat P76. Brightness control was working
before.
$ uname -r
5.4.0-59-generic
$ lspci |grep -i vga
01:00.0 VGA compatible controller: NVIDIA Corporation TU104GLM [Quadro RTX 5000
Mobile / Max-Q] (rev a1)
$ sudo lshw -c video
*-display
description: VGA compatible controller
product: TU104GLM [Quadro RTX 5000 Mobile / Max-Q]
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:01:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
configuration: driver=nvidia latency=0
resources: irq:197 memory:ed000000-edffffff memory:c0000000-cfffffff
memory:d0000000-d1ffffff ioport:2000(size=128) memory:ee080000-ee0fffff
Downgrade to 450 works for me too.
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You received this bug notification because you are a member of Kernel
Packages, which is subscribed to nvidia-graphics-drivers-455 in Ubuntu.
https://bugs.launchpad.net/bugs/1905591
Title:
no brightness control after update from 450 to 455
Status in OEM Priority Project:
New
Status in nvidia-graphics-drivers-455 package in Ubuntu:
Triaged
Bug description:
On my Lenovo X1 Extreme with GPU: NVIDIA Corporation GP107M [GeForce
GTX 1050 Ti Mobile]
Updating to nvidia-driver-455 results in loss of brightness control.
On boot, the laptop display brightness is somewhat less than fully
bright and cannot be changed. The brightness up/down keys do pop up
the gnome gui brightness widget, and /sys/class/backlight/nvidia_0/*
values do change, but the actual display's brightness does not.
Problem occurs with either version of nvidia-driver-455 (the archive
or the ~graphics-drivers/PPA). Normal functionality returns if I
downgrade to any version of nvidia-driver-450.
Note also that manually applying this to
/lib/systemd/system/nvidia-persistenced.service has no effect on the problem:
https://github.com/hugh712/nvidia-graphics-drivers/commit/bccad5ee6444dd8c5c47ba19ea0232106a1086f5
Distributor ID: Ubuntu
Description: Ubuntu 18.04.5 LTS
Release: 18.04
Codename: bionic
kernel: 5.4.0-54-generic #60~18.04.1-Ubuntu SMP Fri Nov 6 17:25:16 UTC
2020 x86_64 x86_64 x86_64 GNU/Linux
nvidia-driver-455: 455.38-0ubuntu0.18.04.1
To manage notifications about this bug go to:
https://bugs.launchpad.net/oem-priority/+bug/1905591/+subscriptions
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