Okay, let's stick with Oneiric. I assume that when the machine comes up with no backlight, adjusting the brightness (by using Hotkeys or the GUI) doesn't work either?
If that's correct, here's a couple of things you can test:
1. see what's in acpi_video/bl_power
2. when you try to adjust the brightness, do acpi_video/brightness and /actual_brightness change? Are they still in sync?
3. control the backlight acpi_video0 manually (by writing to acpi_video0/brightness) and see if /brightness or /actual_brightness change
4. reboot with 'acpi_backlight=vendor' on the command line (& confirm that acpi_video0 no longer shows up in sys/class/backlight) and go through the same routine with intel_backlight
Okay, let's stick with Oneiric. I assume that when the machine comes up with no backlight, adjusting the brightness (by using Hotkeys or the GUI) doesn't work either?
If that's correct, here's a couple of things you can test: brightness and /actual_brightness change? Are they still in sync? brightness) and see if /brightness or /actual_brightness change =vendor' on the command line (& confirm that acpi_video0 no longer shows up in sys/class/ backlight) and go through the same routine with intel_backlight
1. see what's in acpi_video/bl_power
2. when you try to adjust the brightness, do acpi_video/
3. control the backlight acpi_video0 manually (by writing to acpi_video0/
4. reboot with 'acpi_backlight
[the documentation for /sys/class/ backlight is at http:// kernel. ubuntu. com/git? p=ubuntu/ ubuntu- oneiric. git;a=blob_ plain;f= Documentation/ ABI/stable/ sysfs-class- backlight ]
(btw: what's in /sys/class/ backlight on your Maverick system? Are you able to change the brightness on that system?)