[Bug 38104] Thinkpad R50p: Hibernation takes some minutes when running on battery

[Tobias Vogel]

Public bug reported:

Affects: linux-source-2.6.15 linux-image-2.6.15-19-686 (Ubuntu)
       Severity: Normal
       Priority: (none set)
         Status: Unconfirmed


Description:
My Thinkpad R50p shows some strange behaviour with suspend to disk in
Dapper 6.06. When powered on AC, suspend to disk works as expected and
powers down the laptop within some seconds. If I try the same, when
running on battery, the shutdown process takes about 3-5 minutes with
high CPU load (fan rotating at high rpm) until the laptop finally shuts
down.

This bug seems to be related to #29767
https://launchpad.net/distros/ubuntu/+source/linux-source-2.6.15/+bug/29767
(Problems hibernating with docked Thinkpad)

Valentijn Sessink brought up a workaround in the comments of this bug,
by disabling HD write caching in /etc/laptop-mode/laptop-mode.conf
[CONTROL_HD_WRITECACHE=0]. This setting solves the problem and
hibernation works as expected when running on battery. As this setting
is described as potentially harmfull (possible data losses), I filed
this bug, to document the behaviour for others and maybe there's another
solution which isn't considered as problematic as the workaround.

If I can help you out with any further details, let me know.
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Thinkpad R50p: Hibernation takes some minutes when running on battery
https://launchpad.net/malone/bugs/38104