[ltp] Display brightness

[Henrique de Moraes Holschuh]

On Mon, 03 Mar 2008, Joerg Platte wrote:
> problem, but kpowersave does not directly set the configured brightness, 
> instead it increases or decreases the current brightness to the configured 
> level (looks like a sequence of echo up/down > /proc/acpi/ibm/brightness). 

Ick.

> Maybe some time when altering the brightness like this I moved the mouse and 
> an up and an down request is sent more or less at the same time and this 
> confuses thinkpad_acpi?

Moving the mouse shouldn't confuse thinkpad-acpi at all.  Two brightness
change requests *through* thinkpad-acpi at the same time shouldn't confuse
it either, but I will test it to make sure.

What *does* confuse it is to press the brightness up or down key and also
issue any thinkpad-acpi brightness changing commands (through the backlight
interface, or through /proc/acpi/ibm/*) in such a way that both the BIOS
(because of the brightness key) *and* thinkpad-acpi tries to change the
brightness at the sime time.

Also, if *anything* messes with the NVRAM, it will cause thinkpad-acpi to
complain, and I don't believe it will be able to sync NVRAM and EC again
(thus, to stop complaining) until the brightness is either set to maximum or
to the minimum (which are sync points for the firmware).

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh