Public bug reported:

Binary package hint: pm-utils

The problem appeared upon upgrading from Lucid to Maverick-beta.
At every boot, half-way through the boot process the sound of the hard-drive 
changes dramatically and becomes much louder.
The difference is very noticeable, upon hearing it the first time I opened the 
computer case to check what was going on, like if the hard drive got out of its 
place or something !
The whole issue obviously depends on the particular model of hard-drive, and on 
what is its AAM setting upon power-on.
Mine is quite a common model model:
WD Caviar Black 1.0TB  (http://www.wdc.com/en/products/products.asp?driveid=488)

AAM can be enabled/disabled using hdparm -M option and the script that disables 
it during the boot process is:
/usr/lib/pm-utils/power.d/harddrive

Ways to fix the problem:
Temporary fix until next boot, but useful to test the issue: (the /dev/xx entry 
must obviously match your device)
sudo hdparm -M 128 /dev/sda (enables AAM)
sudo hdparm -M 254 /dev/sda (disables AAM)
In-between values might also be recognized by your device.

Permanent fix:
edit the file /usr/lib/pm-utils/power.d/harddrive and change the line
DRIVE_ACOUSTIC_MGMT_AC="${DRIVE_ACOUSTIC_MGMT_AC:-254}"
to
DRIVE_ACOUSTIC_MGMT_AC="${DRIVE_ACOUSTIC_MGMT_AC:-128}"

Proposed solution:
The AAM setting should not be changed by the pm-utils package at all.
The default setting should be whatever the hard-drive manufacturer though was 
the most "normal" setting upon power-on.
For the WD drive mentioned the power-on setting seems quite good, as the noise 
level when disabling AAM would probably be unacceptable for the average user.
Optionally, the user could be given a chance to modify the AAM setting from a 
system configuration tool: "Administration->Disk Utility" could be a good 
candidate.
The option shouldn't be offered by a power-saving configuration tool like 
"Administration->Power Management", because the truth is that AAM doesn't seem 
to be related to power consumption at all !
AAM seems to only affect the noise/performance ratio, and not power 
consumption. This is also confirmed by a TomsHardware review:
http://www.tomshardware.co.uk/terabyte-hitachi-acoustic,review-31458-9.html
As the review points out, power consumption seems to be slightly higher when 
AAM is enabled !
The way the feature is dealt with at present is quite wrong considering the 
mentioned script changes the setting according to whether the computer is 
running on AC or on battery.

** Affects: pm-utils (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: aam hard-drive noise

-- 
During the boot process pm-utils disables "Automatic Acoustic Management" 
making the hard-drive very noisy
https://bugs.launchpad.net/bugs/630856
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