I can confirm this very same problem in my laptop, which is a Thinkpad P1 with a Xeon E-2176M and hybrid Intel / NVIDIA card working in "Discreet" mode (that is, only the NVIDIA card is enabled) using the proprietary NVIDIA driver installed via the nvidia-driver-390 package (390.87-0ubuntu1).
The NVIDIA card is a Quadro P2000 Mobile according to lspci: 01:00.0 VGA compatible controller: NVIDIA Corporation GP107GLM [Quadro P2000 Mobile] (rev a1) I'm currently in Ubuntu 18.10 Cosmic Cuttlefish with kernel 4.18.0-10: $ cat /etc/os-release NAME="Ubuntu" VERSION="18.10 (Cosmic Cuttlefish)" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu 18.10" VERSION_ID="18.10" HOME_URL="https://www.ubuntu.com/"; SUPPORT_URL="https://help.ubuntu.com/"; BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"; PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"; VERSION_CODENAME=cosmic UBUNTU_CODENAME=cosmic $ uname -ar Linux rosmon 4.18.0-10-generic #11-Ubuntu SMP Thu Oct 11 15:13:55 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux And just to confirm, what I'm seeing is this: 1. Pressing the media keys for brightness cause not visible effect (no brightness change), with errors showing up in the journal: oct 23 11:37:47 rosmon gsd-media-keys[2532]: Failed to set new screen percentage: GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._gsd_5fpower_5fmanager_5ferror.Code0: Screen backlight not available oct 23 11:37:47 rosmon gsd-media-keys[2532]: Failed to set new screen percentage: GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._gsd_5fpower_5fmanager_5ferror.Code0: Screen backlight not available 2. Installing xbacklight allows me to effectively change the brightness from the command line (e.g. `xbacklight -set 50`, `xbacklight -inc 10`...) 3. The /sys/class/backlight directory is empty, suggesting that the ACPI interface was not initialize, which I believe is why the media keys don't work and throw that error in the journal (media keys -> gsd-media- keys -> gsd-power-manager -> GUDev -> /sys/class/backlight ACPI interface): $ ls -l /sys/class/backlight/ total 0 4. Booting with acpi_osi= or acpi_osi=Linux causes the /sys/class/backlight directory to be populated with a thinkpad_backlight directory, and the media keys to respond showing the OSD for the brightness, but does not change brightness at all when used: a. The brightness bar is always shown at "random" values between 0 and ~20% b. /sys/class/backlight/thinkpad_backlight/actual_brightness is always 0 Also, in this setup where /sys/class/backlight/ is not empty, xbacklight does NOT work. I hope this is helpful, as it's kind of annoying to have to use xbacklight to change brithgness. I was myself looking into a fix for this, but I can't figure out whether this should be fixed in the NVIDIA driver, some kernel module or somewhere else, so I figured I'd comment here and hope for the best. PS: I can do more tests if needed. Thanks! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1775065 Title: No brightness controls and /sys/class/backlight empty after upgrade to Bionic on laptop with GeForce GTX 1060 Mobile (kernel parameter acpi_osi= is a workaround) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1775065/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
