10.10 Maverick backlight brightness adjustment problem

[tiddlydum]

The backlight's brightness will not change, with neither the fn keys, applet, automatically or with xbacklight. This was a problem I encountered with 10.04, but that was fixed using "nomodeset acpi_backlight=vendor". However, this does not work in 10.10, and actually leads to x server not starting, giving a screen not found error. I've seen a lot of unresolved posts about this, covering many laptops, but for clarification, I'm using an Acer Aspire 5738. Any help would be greatly appreciated.

[Arla]

I'm having the same problem on my Lenovo (Y450), I'm torn right now on whether to revert to 10.04 since that worked properly, but I lose all the program updates

There was a bug-report on launchpad about it, and the implication was this was unlikely to be fixed for a long time.

[tiddlydum]

Oh really? In that case I might revert. I'm not missing much, cos I install most of my stuff outside the package manager. I do hope they fix it, I have no idea why it's happening.

[Arla]

This was the bug, no clue what any of it really means (it's WAY over my head) but the implication is that it may not be fixed for a while, although the last comments from Robert Hooker also imply that it's already been fixed upstream so erm, not sure.

I'm going to probably revert to 10.04 tonight, and then wait for a bit because I'm also having issues with Suspend in 10.10 (sometimes it just fails, but it seems to be very intermittent) 10.04 was solid as a rock, and while I'd like to have the latest Digikam updates, I'll live with the older version for now.

[tiddlydum]

Looks like there's a workaround. I'll post more soon.

[Arla]

Looks like there's a workaround. I'll post more soon.

I'll be interested to see, I know I can manually call setpci to change the brightness, but it's a clunky fix at best, yes it does work, but I think for the price I'll go back to 10.04 and wait for 11.04 to see if that can resolve the issue.

Anyway, if you find a workaround other than the setpci command I'd definitely be interested in hearing.

[tiddlydum]

That was the workaround I was looking at well, I'm seeing if another fix works, and if it doesn't, I'm reverting too.

[rs87424]

The backlight's brightness will not change, with neither the fn keys, applet, automatically or with xbacklight. This was a problem I encountered with 10.04, but that was fixed using "nomodeset acpi_backlight=vendor". However, this does not work in 10.10, and actually leads to x server not starting, giving a screen not found error. I've seen a lot of unresolved posts about this, covering many laptops, but for clarification, I'm using an Acer Aspire 5738. Any help would be greatly appreciated.

yeah i am also using an Acer Aspire with the same problem. I tried to use the brightness app but it didn't work either. earlier versions of ubuntu had this problem as well and the fix was relatively simple but I haven't found anything to fix this one yet..keep looking

[SilverDrake11]

Yea I'm running 64bit Maverick on an Ideapad Y450, and I have the exact same problem. In 10.04, I was able to fix it appending that line to the grub config file, but now that results in the xserver not starting.

[ceefour]

I also cannot control my LCD display brightness of Lenovo Ideapad Z360 in Ubuntu 10.10 Maverick.

SOLUTION FOUND!!!!

See: https://bugs.launchpad.net/dell/+bug/568611/comments/77