Power and brightness issue

[Genes MailLists]

On 08/02/2011 02:41 PM, Adam Williamson wrote:
> On Sun, 2011-07-31 at 15:37 -0300, Sergio Belkin wrote:
>> I've read http://fedoraproject.org/wiki/Bugs/Common#Laptop_screen_dims_when_switching_to_battery_power_or_idle_mode_but_never_brightens_again
>>
>> My system suffers the same symptoms but I use KDE. So it seems that is
>> not GNOME restricted.
>>
>>
>> Using F15 on x86_64
>>
>> cat /sys/module/pcie_aspm/parameters/policy
>> default performance [powersave]
>>
>> any ideas?
> 
> That bug certainly was GNOME specific: it was a bug in
> gnome-power-manager 's logic. There's no way that specific bug could
> affect KDE, unless somehow you're running g-p-m in KDE. If you're seeing
> a similar issue in KDE, it must track down to a different bug, so please
> file it. Be aware, though, that the display dimming somewhat when you
> disconnect the AC power is 'normal': both KDE and GNOME do this to save
> battery power. The bug in this case was that when you re-connected to AC
> the brightness did not increase again, but if you then disconnected from
> AC once more the brightness would decrease further - so you got stuck in
> a descending spiral of darkness until the screen was stuck at its lowest
> possible brightness setting until you adjusted it manually or rebooted.
> If the screen dims somewhat (to, say, 50%) when you unplug, goes back up
> to 100% when you plug back in, then dims back to 50% when you unplug
> again, that's intended behaviour and not a bug (though if you don't like
> it, it's configurable).

  I've seen a different bug on KDE - specifically - after a sleep/resume
cycle (I think) - going to battery off A/C - the applet says its in
powersave mode but the screen is NOT dimmed - using the applet to switch
to performance and then back to powersave mode - dims the screen.

  This is (as far as I know) specific to KDE but I could be wrong ...