[ltp] T61/intel: LCD brightness

[Theodore Tso]

On Mon, Oct 29, 2007 at 01:00:01PM -0200, Henrique de Moraes Holschuh wrote:
> My answer to Ubuntu is, and it has always been "Don't Do That".  It is that
> simple.  Either the thinkpad does it fine by itself (so you must make sure
> you try to change the brightness yourself only if you get brightness up/down
> from an external keyboard or somesuch), or the thinkpad has a proper ACPI
> BIOS that should be used for all brightness changes in sync with whatever
> X.org thinks should happen.

... and one of these days, when someone actually documents the
complicated and convoluted path that that causes signals to go from
the input layer, through hal, dbus, etc., and the complicated set of
scripts and XML configuration files which control said scripts, maybe
I'll try to fix Ubuntu's set up.  (Quite frankly, I consider sysfs and
the whole hal/dbus mess to be a didaster, but it's the politically
correct way to do things, even though /proc/acpi/ibm is so much
simpler and easier to debug.)

Or, maybe sometime Ubuntu will fix the problem and do things the
politically correct way.  I dunno.  In the meantime, it's *so* much
easier just to put put this in /etc/modprobe.d/thinkpad_acpi:

options thinkpad_acpi hotkey=enable,0xffff8f experimental=1 fan_control=1 brightness_enable=1

Is there any downside to using the old /proc/acpi/brightness
interface, other than political correctness --- we-must-do-everything-
the-complicated-XML-way-and-use-unstable-sysfs-path-names-that-are-almost-
impossible-to-use-correctly-from-a-shell-script?

							- Ted