USB: xHCI: update ring dequeue pointer when process missed tds
authorAndiry Xu <andiry.xu@amd.com>
Mon, 9 Aug 2010 20:56:15 +0000 (13:56 -0700)
committerGreg Kroah-Hartman <gregkh@suse.de>
Tue, 24 Aug 2010 03:50:16 +0000 (20:50 -0700)
commit14184f9b8047026f1812f49df074e89dad3a09bc
tree5492adad4d8ce5d263abbdad713c13a35b08202c
parenta1669b2c64a9c8b031e0ac5cbf2692337a577f7c
USB: xHCI: update ring dequeue pointer when process missed tds

This patch fixes a isoc transfer bug reported by Sander Eikelenboom.
When ep->skip is set, endpoint ring dequeue pointer should be updated
when processed every missed td. Although ring dequeue pointer will also
be updated when ep->skip is clear, leave it intact during missed tds
processing may cause two issues:

1). If the very next valid transfer following missed tds is a short
transfer, its actual_length will be miscalculated;
2). If there are too many missed tds during transfer, new inserted tds
may found the transfer ring full and urb enqueue fails.

Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/host/xhci-ring.c