Sebastian Schwarz, Fri 2011-11-11 @ 16:26:24+0100:
After running `xbacklight -set 100` my backlight is at the previous brightness level, which is 57% and not at the 100% xbacklight should set it to.
I see. I usually run my backlight at 100%, so I could be seeing the same thing and not realizing it, as my previous level would be 100% in the usual case.
So 3.1 has probably some new backlight code, which does not work as it should. And indeed there are two threads on the linux.kernel newsgroup[1, 2] and one on the LKML[3] with an explanation, a patch[4] and a couple of bug reports[5, 6, 7].
I have not tested the patch yet, but is seems to deal with the issue at hand.
[1]: https://groups.google.com/group/linux.kernel/browse_thread/thread/28296924e8... [2]: https://groups.google.com/group/linux.kernel/browse_thread/thread/fde3079d9f... [3]: https://lkml.org/lkml/2011/9/19/381 [4]: https://lkml.org/lkml/diff/2011/10/25/473/1 [5]: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/872652 [6]: https://launchpad.net/~kamalmostafa/+archive/stuck-backlight [7]: https://bugs.freedesktop.org/show_bug.cgi?id=41926
Thanks for these links. I'll test the patch on my system tonight when I get some free time. Compiling Linux on my laptop takes forever.