[ltp] Re: [ibm-acpi-devel] thinkpad-acpi release 0.18-20071203 uploaded to ibm-acpi.sf.net

[Dom]

Henrique de Moraes Holschuh wrote:
> On Fri, 15 Feb 2008, jieryn@gmail.com wrote:
>   
>> I have a T61p 7LET56WW (1.26) BIOS 1.38 and am running Gentoo
>> vanilla-sources-2.6.24.2 + thinkpad-acpi-0.19-20080107. This is the first
>> release where Fn+Home and Fn+End actually do something useful inside X!!
>> Thank you!!! :-) From the brightest or darkest, I am able to change
>> brightness levels 15 times.
>>     
>
> There's 20080213 now, please check it to make sure I didn't hork it :)
>
>   
>> When changing brightness, I see that
>> /sys/class/backlight/acpi_video1/actual_brightness is updated. acpi_video0
>> remains constant.
>>     
>
> That's ACPI video at work.  It is broken on 2.6.25-rc, let's hope it gets
> fixed soon :
When I change brightness with Fn+Home/End (BTW, this I believe worked 
out of the box when I installed Debian Sid few months ago, I have ATI 
Mobility Radeon X1300) both the
/sys/class/backlight/acpi_video1/actual_brightness
and
/sys/class/backlight/acpi_video0/actual_brightness
change and the values are always identical - does that mean something?

Also, I only have 7 brightness levels accessible by just using the 
Fn+Home/End and the lowest I can get like that is actual_brightness=30. 
I'm wondering if it would be safe to lower the value by echoing it to 
actual_brightness.

I don't know enough about it and really don't want to break something 
that has worked so far (even though it wouldn't be me if I didn't do 
something like that, but I'm holding myself this time...) so can you 
please forward me to some explanation of all the methods and pitfalls of 
adjusting brightness on ThinkPads with ATI cards? Like what about that 
xbacklight I keep reading about here - I don't have to use it, or would 
I have a better experience with it other than just with ACPI video (that 
has worked out of the box)?

Dom
http://domdelimar.com