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"
updat
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)
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Update : the second way is using i2c to control backlight.
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Title:
backlight brightness control won't work in 2011 iMac 27"
To manage notificatio
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 fai
Affected also.
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Title:
backlight brightness control won't work in 2011 iMac 27"
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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).
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Bu
Status changed to 'Confirmed' because the bug affects multiple users.
** Changed in: gnome-power-manager (Ubuntu)
Status: New => Confirmed
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/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.
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Assigning package.
** Package changed: ubuntu => gnome-power-manager (Ubuntu)
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Title:
backlight brightness control won't work in 2011 iMac 27"
T
