gnome-power-manager displays some values at 1/10 of the correct amount

[Andrew Aylett]

Binary package hint: gnome-power-manager

Gnome-power-manager reports some battery statistics at 1/10 of their true value, while others are correct. For example, the battery current charge, last full charge and design charge are given at 2.4Wh, 2.4Wh and 2.6Wh when the battery was actually built as 26Wh. Similarly, the discharge rate is given as ~1.1W, while it should be 11W. The charge rate, however, is given at 65.5W, which is correct. This also leads to wildly incorrect remaining charge times, with around 1m20s quoted for a 50% charge, which is roughly 40x out.

ProblemType: Bug
Architecture: i386
Date: Sat Aug 15 08:15:45 2009
DistroRelease: Ubuntu 9.10
Package: gnome-power-manager 2.27.5-0ubuntu1
ProcEnviron:
 LC_COLLATE=C
 PATH=(custom, user)
 LANG=en_GB.UTF8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-5.24-generic
SourcePackage: gnome-power-manager
Uname: Linux 2.6.31-5-generic i686

[Paul Sladen (sladen)]

Please can you include the output from running:

  grep -r . /proc/acpi/battery/

[Andrew Aylett (andrew-aylett)]

Attached.

[David Tombs (dgtombs)]

Assigning to acpid since /proc/acpi/battery also reports the wrong values.

[David Tombs (dgtombs)]

Forgive me, correct package is kernel, not acpid. Sorry for the bug spam.

Can you reproduce with the latest kernel, Andrew?

[Andrew Aylett (andrew-aylett)]

Yes, an up-to-date Karmic still exhibits the bug. Thanks for your help, David.

[David Tombs (dgtombs)]

Thanks for the info. Can you also reproduce the bad numbers with "devkit-power --dump"?

[Andrew Aylett (andrew-aylett)]

I've attached the output of devkit-power --dump while discharging.
One change from before is that the power use while discharging is now also out by a factor of 10, which does at least mean that the time remaining is more correct. Power while charging is still correct.

[David Tombs (dgtombs)]

Oh, so is this fixed for you, now? If percentages and time remaining are both correct, but the numbers used internally are wrong, I think that's fine. It's possible your battery just reports incorrect values.

[Andrew Aylett (andrew-aylett)]

There's still one issue, which is that time remaining to charge is significantly out. I've attached a copy of `devkit-power -d` while on charge, with about fifteen minutes to go before fully charged, but reporting 17 seconds.

[David Tombs (dgtombs)]

OK, I'll confirm and let someone more knowledgeable than I am figure out what's going on. Thanks for the info!

[Andrew Aylett (andrew-aylett)]

This is rather more annoying in Lucid, as whenever I move from mains power to battery power, I get a warning that the battery is low and that the system will hibernate soon. I then don't get this notification before the battery really does run out and the system doesn't automatically hibernate when it should.

[Andrew Aylett (andrew-aylett)]

This is still a problem in Maverick: When I disconnect the power, the notification says that I have 0:02 left, and a dialog pops up saying "Laptop battery critically low \n Computer will hibernate very soon unless it is plugged in." The power actually lasts for the best part of two hours, and the indicator applet reports this correctly. When I plug the power back in, the indicator applet thinks it will only take a matter of seconds to charge the battery, no matter how empty it is.

I appreciate that this is probably more an issue with my hardware than with the software, but I've got to live with the hardware and I'd quite like a "fix" in software :).