On Wed, 2007-02-21 at 21:17 -0200, Henrique de Moraes Holschuh wrote:

On Wed, 21 Feb 2007, Richard Purdie wrote:

quoted

enabled. On a thinkpad, the backlight is probably under ACPI control.

BIOS+ACPI, actually.  Without ACPI video loaded, the firmware does
everything correctly.  With ACPI video, the firmware does it, then its
changes are clobbered over by ACPI video's.

If ibm-acpi is loaded, a backlight device "ibm" is added.  ibm-acpi's ibm
backlight device can change the display brightness.  It is *not* capable of
turning the backlight on or off, AFAIK.

BTW, some ThinkPads don't have a Radeon, but rather an Intel GM/GMX device.

I have a thinkpad with Intel GM graphics ;-). I need it to work so I try
not to experiment too much on it. I've just tried the ibm-acpi driver
and it doesn't work well :-(.

So far I've noticed:

* 'cat brightness' != 'cat actual_brightness' upon bootup (doesn't have
to be true if there is hardware brightness limiting or level changing in
action but that wouldn't be the case here and this could be fixed
easily).
* 'echo 0 > brightness' lowered the intensity but by a level or two, not
set it to level 0. A couple of more attempts and it did jump from 7 -> 1
and so on, it seems erratic.

actual_brightness always seems to be correct, as does brightness so it
looks like its not updating the hardware correctly.

Regards,

Richard








-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV