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Bug#751408: linux-3.2: xhci_hcd: "ERR: no room for command on command ring"

Source: linux
Version: 3.2.57-3
Severity: important


On some laptops such as HP's ZBook 15 that only have USB 3 ports, I
can reproducibly make the kernel ignore usb devices, in which case
syslog reads as follows:

ERROR no room on ep ring
ERR: No room for command on command ring
device not accepting address 5, error -12
couldn't allocate port 6 usb_device

So far I have reproduced it by plugging a USB 2.0 device on any of the
ports, by doing it several times (plugging & unplugging) the kernel
reaches the state where plugging again any device leads to the above

Searching for the error message on $subject it shows several reports
of the same problem.

This problem can no longer be reproduced with a  kernel backported
from jessie/sid.

So, searching a bit on the git log leads to the following commits:

"xhci: Reset reserved command ring TRBs on cleanup. " - likely to fix
the no room for command bug

"xHCI: add aborting command ring function" - unlikely to be it, but
maybe a fix for other bugs

"xHCI: dynamic ring expansion" - likely to fix other bugs, and maybe
help on this one

I intend to test those, but sending the report in advance.

Raphael Geissert - Debian Developer
www.debian.org - get.debian.net

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