Ubuntu doesn't keep screen brightness

[masterus]

hi,
have Ubuntu 8.04.1 lts on my T43 , have problem with screen brightness.
Ubuntu doesnt keep same level of brightness.
so from time to time have to press Fn+Home to correct that , also when doing that have brightness icon on screen but bar doesnt make progress
could anyone help me with that
would be very gratefull for all answers
rgds,

[dk]

I haven't seen this before but are you on the same power source when the brightness changes (ie. on AC power the entire time) or are you switching power sources like from AC to battery?

Can you try `cat /proc/acpi/video/VID/LCD0/brightness' before and after the brightness changes?

[maciejs]

Yeah, you haven't really provided much details... H'anyway, just go to "Power Management" and untick 'Dim Display When Idle' in AC and/or Battery tabs.

Something similar was happening to me by the way and that's how I fixed it...

[masterus]

hi,
to dk and maciejs: yesterday have seen when am on ac then ubuntu keeps brightness
so it looks like have issue only when am on battery
now am on battery and tried: cat /proc/acpi/video/VID/LCD0/brightness but got reply: <not supported>
any idea
rgds,

[bajaman61]

hi,
have Ubuntu 8.04.1 lts on my T43 , have problem with screen brightness.
Ubuntu doesnt keep same level of brightness.
so from time to time have to press Fn+Home to correct that

You did not mention doing so, so I will suggest you also check under System ==> Power Management. The setting there should be reviewed first.

Second, there is considerable dicussion about this feature -- but from the other side. Ubutuntooers lobbied for energy saving power management features -- even saying the MicroSoft had a better system.

Another possibility is that many specialty functions need activation or a new key combination to activate them when you migrate over to any Linux system.

The issue is discussed, and a possible programmatic patch is offered on the Ubuntu forum here:
http://brainstorm.ubuntu.com/idea/81/

Sometimes on person's battery saving utility is another person's annoyance.

Trust some of this will be helpful.

[mikeh]

X40 here, and the screen brightness (and everything else) works perfectly on 8.04., but not 8.10. You might want to install 8.04 (hardy).

[maciejs]

go to "Power Management" and untick 'Dim Display When Idle' in AC and/or Battery tabs.

Don't know about you guys but that worked for me. If it still doesn't work you might want to try Mint - version 6 RC just came out and in my experience Mint tend to be more polished while fully compatible with Ubuntu. I haven't tried 6 myself yet (well, only as a virtual machine but that doesn't really count) - maybe I will today when I have a spare moment or two...