The same for me, xps13, full hd, booting from UEFI. Working well with previous kernel version (3.8.0-29-generic). After updating to the latest (3.8.0-30-generic) the problem is back again.
martin@flegy-nb:~$ uname -a
Linux flegy-nb 3.8.0-30-generic #44-Ubuntu SMP Thu Aug 22 20:52:24 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
martin@flegy-nb:~$ cat /etc/issue
Ubuntu 13.04 \n \l
When I am trying to change backlight (f4/f5) I see changes in
The same for me, xps13, full hd, booting from UEFI. Working well with previous kernel version (3.8.0-29-generic). After updating to the latest (3.8.0-30-generic) the problem is back again.
martin@flegy-nb:~$ uname -a
Linux flegy-nb 3.8.0-30-generic #44-Ubuntu SMP Thu Aug 22 20:52:24 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
martin@flegy-nb:~$ cat /etc/issue
Ubuntu 13.04 \n \l
When I am trying to change backlight (f4/f5) I see changes in
/sys/class/ backlight/ intel_backlight /actual_ brightness
but without any effect on the backlight