I have a Dell XPS 15 9570 with the same issue. This includes the slider
in the top panel menu, in system settings and when using the keyboard
shortcuts. When using the keyboard shortcuts, the OSD shows and the bar
moves but the screen brightness is not changed.
System: Host: rex Kernel: 5.4.0-14-generic x86_64 bits: 64 Desktop: Gnome
3.35.91 Distro: Ubuntu 20.04 LTS (Focal Fossa)
Machine: Type: Laptop System: Dell product: XPS 15 9570 v: N/A serial: <root
required>
Mobo: Dell model: 0D0T05 v: A00 serial: <root required> UEFI: Dell
v: 1.15.0 date: 12/25/2019
Battery: ID-1: BAT0 charge: 36.1 Wh condition: 36.1/56.0 Wh (64%)
CPU: Topology: 6-Core model: Intel Core i7-8750H bits: 64 type: MT MCP L2
cache: 9216 KiB
Speed: 800 MHz min/max: 800/4100 MHz Core speeds (MHz): 1: 800 2:
800 3: 800 4: 800 5: 800 6: 800 7: 800 8: 800
9: 800 10: 800 11: 800 12: 800
Graphics: Device-1: Intel UHD Graphics 630 driver: i915 v: kernel
Device-2: NVIDIA GP107M [GeForce GTX 1050 Ti Mobile] driver: N/A
Display: x11 server: X.Org 1.20.7 driver: modesetting,nvidia
unloaded: fbdev,nouveau,vesa
resolution: 1920x1080~60Hz
OpenGL: renderer: Mesa Intel UHD Graphics 630 (CFL GT2) v: 4.6 Mesa
20.0.0
Audio: Device-1: Intel Cannon Lake PCH cAVS driver: snd_hda_intel
Device-2: Texas Instruments PCM2902 Audio Codec type: USB driver:
hid-generic,snd-usb-audio,usbhid
Sound Server: ALSA v: k5.4.0-14-generic
Network: Device-1: Intel Wireless-AC 9260 driver: iwlwifi
IF: wlp59s0 state: up mac: 20:79:18:e7:0b:8f
Device-2: ASIX AX88179 Gigabit Ethernet type: USB driver:
ax88179_178a
IF: enx000ec6c5cd04 state: up speed: 1000 Mbps duplex: full mac:
00:0e:c6:c5:cd:04
Drives: Local Storage: total: 1.14 TiB used: 719.10 GiB (61.5%)
ID-1: /dev/nvme0n1 vendor: Toshiba model: KXG50ZNV256G NVMe 256GB
size: 238.47 GiB
ID-2: /dev/sda vendor: Crucial model: CT1000MX500SSD1 size: 931.51
GiB
Partition: ID-1: / size: 87.75 GiB used: 10.80 GiB (12.3%) fs: ext4 dev:
/dev/nvme0n1p2
ID-2: swap-1 size: 14.90 GiB used: 0 KiB (0.0%) fs: swap dev:
/dev/nvme0n1p5
Sensors: System Temperatures: cpu: 52.0 C mobo: N/A
Fan Speeds (RPM): cpu: 2476 fan-2: 2499
Info: Processes: 340 Uptime: 1h 55m Memory: 15.39 GiB used: 4.40 GiB
(28.6%) Shell: bash inxi: 3.0.37
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux-5.4 in Ubuntu.
https://bugs.launchpad.net/bugs/1865346
Title:
Changing backlight no longer works with Linux 5.4
Status in linux-5.4 package in Ubuntu:
Confirmed
Bug description:
As of upgrading to Ubuntu 20.04 (and with it Linux 5.4), adjusting
brightness no longer works. `/sys/class/backlight/intel_backlight/`
exists, but writing to
`/sys/class/backlight/intel_backlight/brightness` doesn't have any
effect. If I boot into Linux 5.3 instead, changing brightness works
again. Complete dmesg output is attached, but I don't see anything
interesting in it.
My hardware is a Dell Inc. XPS 15 9575, with an Intel Core i7-8705G.
More info:
`lsb_release -rd`:
Description: Ubuntu Focal Fossa (development branch)
Release: 20.04
`apt-cache policy linux-generic`:
linux-generic:
Installed: 5.4.0.14.17
Candidate: 5.4.0.14.17
Version table:
*** 5.4.0.14.17 500
500 http://no.archive.ubuntu.com/ubuntu focal/main amd64 Packages
100 /var/lib/dpkg/status
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-5.4/+bug/1865346/+subscriptions
--
Mailing list: https://launchpad.net/~kernel-packages
Post to : kernel-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~kernel-packages
More help : https://help.launchpad.net/ListHelp
