Just to add to the report by @manzood, this bug affects my variant of y540 as well. My complete laptop spec is as follows: Lenovo Legion Y540 NVIDIA GTX 2060 Mobile Ubuntu 18.04 kernel 5.4.0-72-generic
and again, the workaround suggested by @sureshot16 does not work, editing /sys/class/backlight/acpi_video0/brightness does not work(except when prime-select is set to intel), adding 'Option "RegistryDwords" "EnableBrightnessControl=1"' to /usr/share/X11/xorg.conf.d/10-nvidia-brightness.conf does not work neither does adding kernel parameters in grub config. This brightness issue has been a thorn in my side for the better part of a year, the only version which works is the Nouveau display driver installed via "Software & Updates" but has no CUDA support or Steam integration so that's a deal breaker for me. Unlike @manzood, suspending the laptop and resuming has never worked for me and causes artifacts and flickering in 460 specifically. Issue persists in 465 as well. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to nvidia-graphics-drivers-460 in Ubuntu. https://bugs.launchpad.net/bugs/1905591 Title: no brightness control in {455,460} after update from 450 Status in OEM Priority Project: New Status in nvidia-graphics-drivers-455 package in Ubuntu: Confirmed Status in nvidia-graphics-drivers-460 package in Ubuntu: Confirmed Bug description: On my Lenovo X1 Extreme with GPU: NVIDIA Corporation GP107M [GeForce GTX 1050 Ti Mobile]: WORKS FINE: nvidia-driver-450: 450.102.04-0ubuntu0.18.04.1 NO BRIGHTNESS CONTROL: nvidia-driver-455: 455.38-0ubuntu0.18.04.1 nvidia-driver-460: 460.32.03-0ubuntu0.18.04.1 nvidia-driver-460: 460.39-0ubuntu0.18.04.1 *WORKAROUND: See comment #11 (add nvidia drivers to initramfs). *Note that 460 fixes it for a 20.04 ThinkPad P73 per comment #6, but not for my 18.04.5 Lenovo ThinkPad X1 per comment #5. Updating to nvidia-driver-455 (or -460) 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) or any version of -460. Normal functionality returns if I downgrade to any version of nvidia- driver-450. Also observed: 455 and 460 temporarily display some pixel garbage while mode-switching during the graphic login sequence. Only a minor glitch, but note that 450 does not exhibit that issue either. 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 To manage notifications about this bug go to: https://bugs.launchpad.net/oem-priority/+bug/1905591/+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
