Bug 11679 - MSI Wind U100 - /sys/class/power_supply/ADP1/online always contains 1
Summary: MSI Wind U100 - /sys/class/power_supply/ADP1/online always contains 1
Status: CLOSED DUPLICATE of bug 10724
Alias: None
Product: ACPI
Classification: Unclassified
Component: EC (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Alexey Starikovskiy
Depends on:
Reported: 2008-09-30 15:31 UTC by Rafael J. Wysocki
Modified: 2008-10-17 14:32 UTC (History)
2 users (show)

See Also:
Kernel Version: 2.6.27-rc8
Regression: ---
Bisected commit-id:

update sysfs state on every access (937 bytes, patch)
2008-09-30 23:34 UTC, Alexey Starikovskiy
Details | Diff
Output of acpidump (110.96 KB, text/plain)
2008-10-01 04:19 UTC, Rafael J. Wysocki
debug ac notify propagation (1.67 KB, patch)
2008-10-01 05:33 UTC, Alexey Starikovskiy
Details | Diff

Description Rafael J. Wysocki 2008-09-30 15:31:52 UTC
Distribution: openSUSE 11.0
Hardware Environment: MSI Wind U100
Problem Description: If the "new" sysfs interface for the AC adapter is not compiled out, the AC adapter is always reported as present, even if it's been unplugged.  The reason for this is apparently that the sysfs attribute /sys/class/power_supply/ADP1/online always contains a '1', even if the adapter is not present.

At the same time, /proc/acpi/ac_adapter/ADP1/state contains the right value if the AC adapter has been unplugged, so there seems to be a bug somewhere in the notification code.

Steps to reproduce: Unplug the AC adapter and look at kpowersave.
Comment 1 Alexey Starikovskiy 2008-09-30 23:14:14 UTC
please provide acpidump output.
Comment 2 Alexey Starikovskiy 2008-09-30 23:34:19 UTC
Created attachment 18124 [details]
update sysfs state on every access

This should help, but it is definitely interesting why there is no notify.
Comment 3 Rafael J. Wysocki 2008-10-01 04:19:51 UTC
Created attachment 18127 [details]
Output of acpidump
Comment 4 Rafael J. Wysocki 2008-10-01 04:22:37 UTC
(In reply to comment #2)
> This should help, but it is definitely interesting why there is no notify.

I'll test it later today, but I'm not sure if it's going to help, unless the userland polls the sysfs attribute.
Comment 5 Alexey Starikovskiy 2008-10-01 05:33:34 UTC
Created attachment 18133 [details]
debug ac notify propagation

Rafael, please check with this patch,
there should be some more printouts for each AC state change.
Comment 6 Rafael J. Wysocki 2008-10-01 12:35:01 UTC
With this applied I've got a single notification when the after unplugging the AC adapter.  However, I haven't got any notification after replugging it (actually i tried to unplug/replug it several times in a row, but there only was one notification).

The relevant lines in dmesg are:

ACPI: EC: expect AC state update
ACPI: received notify of state change
Comment 7 Rafael J. Wysocki 2008-10-01 13:10:14 UTC
The patch from http://bugzilla.kernel.org/show_bug.cgi?id=10724#c142 fixes the problem.  Closing as a duplicate.

*** This bug has been marked as a duplicate of bug 10724 ***

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