When I'm on battery, gnome power manager will forcefully set the brightness to the level it wants, and not let me manually adjust using the brighness setting buttons. It will force the brightness back down as soon as I try to adjust. Even worse, even if I set the setting to dim 0% it will /still/ force the backlight into it's lowest setting as soon as I try to adjust. I have to re-open gnome-power-preferences and it'll jump back up to 100% bright. This is extremely frustrating.
I can reproduce this even with ac power plugged in. Adjusting downwards works, going back up resets to zero. This is with the Fujitsu test laptop at my desk. I don't see on the laptop I use most of the time since hal doesn't see the panel and so g-p-m doens't try to do anything with the backlight
Thinkpad T60 is also affected. This makes gnome-power-manager too annoying to use for me.
Adding the upstream maintainer to Cc.
Many laptops successfully handle their own brightness adjustments when on AC or battery. Some laptops don't. Why not disable gnome-power-manager's fscking with the brightness by default, and whitelist laptops who need it?
It's different than that. You may still want autodimming when inactive and such. Basically the division is the groups of laptops where keyboard adjustment of the brightness emits a keycode and those that don't. Those that don't should be blacklisted from having gpm try to do anything with the brightness as it can't ever have an accurate idea of what the state is. Those that do emit a keystroke should be fine so long as hal, et al know about it and can track it. Of course this just needs more infrastructure in hal(-info) I do believe, not something we can just toss together for F8. For F8 I would propose we just disable this feature by default in g-p-m, and try again in F9 with hal support for blacklisting sets of hardware.
When you say 'manually', are you uisng keys or the applet?
Keys.
I think just unchecking the "Dim when idle" checkbox will make g-p-m DTRT. Please reopen if this isn't the case.