xhci: Reset reserved command ring TRBs on cleanup.
authorSarah Sharp <sarah.a.sharp@linux.intel.com>
Tue, 8 May 2012 14:09:26 +0000 (07:09 -0700)
committerSarah Sharp <sarah.a.sharp@linux.intel.com>
Fri, 18 May 2012 22:41:51 +0000 (15:41 -0700)
commit33b2831ac870d50cc8e01c317b07fb1e69c13fe1
treeaf10fc67df911b3ccd02e455b87f668613098986
parentf8a9e72d125f4e00ec529ba67b674321a1f3bf31
xhci: Reset reserved command ring TRBs on cleanup.

When the xHCI driver needs to clean up memory (perhaps due to a failed
register restore on resume from S3 or resume from S4), it needs to reset
the number of reserved TRBs on the command ring to zero.  Otherwise,
several resume cycles (about 30) with a UAS device attached will
continually increment the number of reserved TRBs, until all command
submissions fail because there isn't enough room on the command ring.

This patch should be backported to kernels as old as 2.6.32,
that contain the commit 913a8a344ffcaf0b4a586d6662a2c66a7106557d
"USB: xhci: Change how xHCI commands are handled."

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
drivers/usb/host/xhci-mem.c