[Bug 1912887] Re: Acer Aspire 5742g backlight brightness level is not saved on shutdown
I made a couple more tests and here is what I've found out. When the backlight is managed by radeon, writing to /sys/class/backlight/radeon_bl0/brightness doesn't do anything. Although changing brightness with Fn+Left/Fn+Right works but the value in /sys/class/backlight/radeon_bl0/brightness doesn't match the actual brightness at all: it can be 250 but the screen would be really dim and vice versa. When I use the kernel without radeon and drm so the backlight is managed by acpi_video, writing to "/sys/class/backlight/acpi_video0/brightness" works fine, the value is saved and restored properly unless it was set to the maximum. In both cases the brightness is reset on shutdown to the lowest possible value and it's always the same on the bios boot screen. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1912887 Title: Acer Aspire 5742g backlight brightness level is not saved on shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1912887/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1912887] Re: Acer Aspire 5742g backlight brightness level is not saved on shutdown
I think it is, because changing "/sys/class/backlight/radeon_bl0/brightness" by systemd-backlight doesn't work. So it can be 1) brightness won't be change for first time, or 2) brightness can't be changed early. Either way, it's a driver bug. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1912887 Title: Acer Aspire 5742g backlight brightness level is not saved on shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1912887/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1912887] Re: Acer Aspire 5742g backlight brightness level is not saved on shutdown
I don't think this is radeon or drm bug: the problem appears with legacy fglrx driver, in custom kernel built without radeon and drm support in rescue mode, and in systems that don't use any of them. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1912887 Title: Acer Aspire 5742g backlight brightness level is not saved on shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1912887/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1912887] Re: Acer Aspire 5742g backlight brightness level is not saved on shutdown
Please file a bug against AMD graphics: https://gitlab.freedesktop.org/drm/amd/issues -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1912887 Title: Acer Aspire 5742g backlight brightness level is not saved on shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1912887/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1912887] Re: Acer Aspire 5742g backlight brightness level is not saved on shutdown
The problem still appears in the latest mainline kernel. Linux unti1x-laptop 5.11.0-051100rc4-generic #202101180234 SMP Mon Jan 18 02:36:59 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1912887 Title: Acer Aspire 5742g backlight brightness level is not saved on shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1912887/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1912887] Re: Acer Aspire 5742g backlight brightness level is not saved on shutdown
Please test latest mainline kernel without "acpi_osi=Linux": https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.11-rc4/amd64/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1912887 Title: Acer Aspire 5742g backlight brightness level is not saved on shutdown To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1912887/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs