Gentoo Archives: gentoo-user

From: Andrew Tselischev <andrewts@×××××××××.net>
To: gentoo-user@l.g.o
Subject: [gentoo-user] USB power management
Date: Thu, 02 Jan 2014 17:16:48
Message-Id: 20140102171631.GA14893@thinkpad-gentoo-89r
1 Hello list,
3 Recently I came into possession of an external USB hard drive. The
4 user's manual (obviously) stated that I should always use "safe removal
5 function" prior to disconnecting the hard drive. I suspect the purpose
6 of this is to tell the device to properly park the heads and power down,
7 but I don't have any idea how to do that on linux.
9 I tried writing '3' to /sys/bus/usb/device/.../power/autosuspend and
10 'auto' to /sys/.../power/control but this doesn't power down the drive.
11 I do hear the indicative "click" after 3 seconds (at least I think I do),
12 but the "PWR" led still stays on, /sys/.../power/runtime_status still
13 says "active" (instead of "suspended") and I can access the data on the
14 block device /dev/sdb, all of which suggests that the drive is still
15 powered on.
17 So, perhaps you could give me a tip on how to properly detach USB
18 drives or link me to an up-to-date information about the kernel's USB
19 subsystem.
22 I should mention that I'm not using any of the over-complicated DEs,
23 just the bare bones X server with awesomewm and a terminal emulator.
25 I'm currently running kernel version 3.12.6-gentoo with udev-208 and
26 udisks-2.1.1


Subject Author
Re: [gentoo-user] USB power management Mick <michaelkintzios@×××××.com>