Re: USB data corruption except in single user mode
jidanni@jidanni.org (jidanni@jidanni.org on 2011-05-11 21:58 +0800):
> What does it mean here on sid, when plugging in memory cards works
> fine in single user mode, with only
[..]
> running, but then in multi user mode, with
[..]
> running, plugging in many of the same memory cards results in
> device not accepting address
> device descriptor read/64, error -71
> etc. etc.
> Even data corruption -- gee thanks.
Just a wild guess - in single-user mode, USB power saving is not
enabled. do a
$ cat /sys/module/usbcore/parameters/autosuspend
to check. But this is really a stretch, autosuspend is controlled
through modprobe so should work the same in any boot mode.
You might also want to check if the same usb modules are loaded in both
modes. Use
$ lsmod |grep hci
to check.
> What process is fighting for the USB connection. I use
> # Change to zero to disable usbmount
> ENABLED=0
> so what others might be the culprit?
This sort of thing can drive you nuts. I've had this problem a few
years ago, and it's really hard to find out what's really wrong. Let's
just say that not all USB devices are created equal. See
http://www.spinics.net/lists/linux-usb/msg33539.html and its thread for
an example.
My problem eventually turned out to be an underpowered external USB
hub, even though the failing devices were not connected through that
hub, and the hub itself appeared to be working fine. Giving the hub its
own power supply resolved the issue.
If you can reliably reproduce this, you still might want to take it up
on the linux-usb mailing list.
Good luck,
Arno
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