Hi,
it was reported to us that some buggy hard drives did not support well
the Tails APM settings, with at least one user experiencing issues
such as:
http://www.thinkwiki.org/wiki/Problem_with_hard_drive_clicking
https://bugs.launchpad.net/ubuntu/+source/acpi-support/+bug/59695
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=448673
I believe the bugfix/less-aggressive-hard-disk-APM-on-AC branch fixes
this, by setting an APM level of 254 on AC power, thus allowing owners
of such buggy hardware to work on AC power and workaround the issue.
(As a bonus, the branch also allows the drive to actually go to
standby mode on battery.)
Please review & merge into stable and devel.
commit 65c78a5594ba7fff98683959d46bf431a065b77d
Author: Tails developers <amnesia@???>
Date: Fri Mar 1 13:17:54 2013 +0100
Enable laptop-mode-tools hard drive power management settings.
Set APM level to 127 on battery, and to 254 on AC power, as a Wheezy desktop
system does.
254 is chosen to avoid causing excessive head load/unload cycles.
127 is chosen because the head parking is very useful for shock protection.
Detailed test results
=====================
Thinkpad X32 with some modern 320GB drive in.
Tails 0.17
----------
* APM_Level = 128 on battery and AC power
* load cycles count is constant on AC power and on battery; according
to `hdparm -C`, the drive stays idle (and load cycle increases only
by one 10 minutes later, maybe caused by the single SMART query
needed to get this data).
Tails 0.17 + bugfix/less-aggressive-hard-disk-APM-on-AC
-------------------------------------------------------
* APM_level = 254 on AC power, 127 on battery
* load cycles count is constant on AC power and on battery
- on battery: according to `hdparm -C`, the drive stays in standby
- on AC: according to `hdparm -C`, the drive stays idle (and given
laptop_mode is disabled at this point,
`NOLM_HD_IDLE_TIMEOUT_SECONDS=7200` so that will eventually
change)
Cheers,
--
intrigeri
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