Kernel updated around May 20th gives poor battery life

[QT]

Before the new kernel I could get 5 or 6 hours battery life, now 3 or 4 if I'm lucky.

CPU is about as busy. Could be related to not being able to change screen brightness.

[Kent Baxley (kentb)]

Need more info please. What kernel, ubuntu release, etc.

[Tomasz Surowiec (tsurowiec)]

xps 1080p, ubuntu 13.04, kernel 3.8.0-23-generic

I confirm problems with brightness control that happened after update in the late may...
hud is working (F4, F5), the brightness is not affected. Brightness if at full setting...

I even made a fresh install of 13.04 - it was working just fine until the apt-get upgrade...

in /sys/class/backlight are : acpi_video0 and intel_backlight

operating with F4 and F5, hud changes the values of file: /sys/class/backlight/acpi_video0/brightness,

none of the previous fixes with disabling acpi, manual changing the value in /sys/class/backlight/intel_backlight works...

if you need some more info, just name the command

[Kent Baxley (kentb)]

If the battery life issues are due to a broken backlight control, then this is a duplicate of the current bug opened against 13.04.

[penalvch (penalvch)]

QT, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p linux <replace-with-bug-number>

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]