Public bug reported:
After launching Kubuntu and logging in to KDE I mount a USB storage
device to e.g. /mnt/tmp and try the following command:
dd if=/dev/zero of=/mnt/tmp/testfile bs=16M count=100
I don't wait until it finishes, because when I press Ctrl+C, it waits
several more seconds and prints that it has copied only one record and
the speed was from 200 kB/s to 1.8MB/s, which is nowhere near the speed
the device can operate.
On the other hand, if I rename /usr/lib/upower/upowerd and restart, the
same command finishes in under a minute and says the speed was >30MB/s
for USB3 and ~30MB/s for USB2 devices/ports.
This hasn't happened on Kubuntu 12.04, but does happen on 14.04.
Running powertop at the "Tunables" tab doesn't show any difference, so it
doesn't look related to autosuspend or similar things.
This also happens with Kubuntu 14.04 LiveCD, not only with the already
installed system.
I've tested this with 3 different USB devices: Transcend JF780 16GB (in
USB 3.0 and 2.0 ports), OCZ ATV 8GB (USB 2.0 device) and Seagate SRD00F2
2TB (in USB 3.0 and 2.0 ports) with identical results.
ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: upower 0.9.23-2ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-30.55-generic 3.13.11.2
Uname: Linux 3.13.0-30-generic i686
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: i386
CurrentDesktop: KDE
Date: Wed Jul 16 00:29:34 2014
InstallationDate: Installed on 2014-05-26 (50 days ago)
InstallationMedia: Kubuntu 14.04 LTS "Trusty Tahr" - Release i386 (20140416.1)
SourcePackage: upower
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: upower (Ubuntu)
Importance: Undecided
Status: New
** Tags: apport-bug i386 trusty
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https://bugs.launchpad.net/bugs/1342341
Title:
upowerd kills USB performance
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