[ltp] T510i backlight

[Jussi Larjo]

Hello,

I have a problem with the backlight of my T510i running Ubuntu 10.10, 
all other ACPI functions on this computer seem to work as usual. The 
brightness setting does not respond to hotkeys or power saving settings, 
neither manually echoing settings to 
/sys/class/backlight/acpi_video0/brightness. The brightness is normally 
at maximum, but sometimes very dim, only suspend/wakeup cycle will 
restore it to maximum.

Echo and hotkey change the value in the sys file but have no real effect.

dmesg log:


[   16.529836] thinkpad_acpi: ThinkPad ACPI Extras v0.24
[   16.529838] thinkpad_acpi: http://ibm-acpi.sf.net/
[   16.529840] thinkpad_acpi: ThinkPad BIOS 6MET61WW (1.24 ), EC 
6MHT38WW-1.13
[   16.529841] thinkpad_acpi: Lenovo ThinkPad T510, model 43149VG
[   16.530073] thinkpad_acpi: detected a 16-level brightness capable 
ThinkPad
[   16.530348] thinkpad_acpi: radio switch found; radios are enabled
[   16.530362] thinkpad_acpi: This ThinkPad has standard ACPI backlight 
brightness control, supported by the ACPI video driver
[   16.530364] thinkpad_acpi: Disabling thinkpad-acpi brightness events 
by default...
[   16.534484] thinkpad_acpi: rfkill switch tpacpi_bluetooth_sw: radio 
is blocked
[   16.537792] thinkpad_acpi: rfkill switch tpacpi_wwan_sw: radio is 
unblocked
[   16.538073] Registered led device: tpacpi::thinklight
[   16.538104] Registered led device: tpacpi::power
[   16.538123] Registered led device: tpacpi::standby
[   16.538144] Registered led device: tpacpi::thinkvantage
[   16.540528] thinkpad_acpi: Standard ACPI backlight interface 
available, not loading native one.
[   16.540731] thinkpad_acpi: Console audio control enabled, mode: 
monitor (read only)
[   16.543847] input: ThinkPad Extra Buttons as 
/devices/platform/thinkpad_acpi/input/input8


Thanks,
Jussi Larjo