Screen brightness does not change on Toshiba Satellite in Karmic

[eOgas]

I've just purchased a new Satellite T135 and installed a fresh copy of Karmic Koala on it. Pretty much everything works great right out of the box. I had to use ndiswrapper for wireless, but it wasn't a huge hassle. Unfortunately, there seems to be a hardware issue with the brightness changing.

The brightness is controlled using a combination of Fn and F keys. The strange thing is that Karmic actually responds to the key presses, and changes the brightness value. But this is not reflected in the actual brightness of the screen. I have tried brightness applet by itself as well to no avail. Also, the screen does not automatically dim when it is taken off of AC power. It almost appears to be 'stuck' on full brightness at all times.

It isn't a huge issue, but I can get 9 hrs of battery life in Windows 7, and only about 6.5 in Karmic, and I suspect that this issue is the largest factor. Any help would be appreciated.

[eOgas]

bump

[phrizek]

I'm having the exact same problem with a new laptop as well. It is a different make/model than yours so I am wondering if this is a widespread problem in 9.10. I've searched the forums and other have reported similar issues. I wonder if there is a bug report on this...

[X1R1]

same thing here, on an Acer 5810TZ, on 9.04 I was able to just type this in a terminal:

xrandr --output LVDS --set BACKLIGHT_CONTROL native

And I can control the brightness perfectly. But now on karmic if I execute that command I get:

X Error of failed request:  BadRROutput (invalid Output parameter)
  Major opcode of failed request:  149 (RANDR)
  Minor opcode of failed request:  15 (RRGetOutputProperty)
  Serial number of failed request:  30
  Current serial number in output stream:  30

Any help would be appreciated

[eOgas]

X1R1, I just tried your xrandr command and I get the exact same error. As this is a new laptop, I've only run Karmic on it, but from the sounds of it, this is a Karmic specific problem.

I'm doing a little research into what could be going on with xrandr.

[eOgas]

Okay, I've now got brightness controls working perfectly. I used the fix discussed in this post: http://ubuntuforums.org/showthread.php?t=121742

Basically, all you do is edit /etc/default/grub You add 'nomodeset acpi_backlight=vendor' to the GRUB_CMDLINE_LINUX_DEFAULT line.

Everything works as expected, except for some reason the lowest brightness setting turns the screen off completely. I don't know whether or not this is a feature or a bug. Either way, I'm satisfied with this fix. I hope it works for you guys too.