[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27"
Found one easy solution (a least on Ubuntu 20.04) to implement manually solution by changing grub configuration. Edit /etc/default/grub To the parameter GRUB_CMDLINE_LINUX_DEFAULT add "acpi_backlight=vendor" The line should be GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor" update grub sudo update-grub reboot Don't know how to implement this in ubuntu distribution. Is it possible to create specific grub config during the installation process ? -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
Did someone tryed this solution : http://www.webupd8.org/2012/08/fix-dell-xps-13-backlight-brightness.html ? Maybe this works (can't try, I'm under 11.04) -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
Update : the second way is using i2c to control backlight. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
ACPI DSDT has actually two paths for changing backlight. One is simple to understand and is using SMI Command Port B2, but only works when booting with BIOS. The other is quite complicated (for me acpi noob) and is using a ressource called smbus-ddcblc. I don't know if the backlight acpi is failing because it doesn't follow the right code path (in which case acpi think it's bios where it isn't) or because memory is not mapped as acpi thinks it should be, or... ? -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
Affected also. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
Update : linux 3.2-rc7 boots that imac 12,2 in EFI mode without any patch or trick. radeon drm is working. Brightness is not. I dualboot on osx to change the backlight, which is saved and restored upon reboot (or halt). -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
/sys/class/backlight/acpi_video0/brightness is present, but does not have any effect when imac is booted in EFI mode. It does work when booted in legacy BIOS mode. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
Status changed to 'Confirmed' because the bug affects multiple users. ** Changed in: gnome-power-manager (Ubuntu) Status: New = Confirmed -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
[Bug 818826] Re: backlight brightness control won't work in 2011 iMac 27
Assigning package. ** Package changed: ubuntu = gnome-power-manager (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/818826 Title: backlight brightness control won't work in 2011 iMac 27 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/818826/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
