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authorAlan Stern <stern@rowland.harvard.edu>2013-01-30 16:36:40 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-31 10:14:48 +0100
commit3e619d04159be54b3daa0b7036b0ce9e067f4b5d (patch)
treeacc77a30daea819c03bcb9edabedf30a38a661d0 /drivers/usb/host/ehci-sched.c
parentb09a61cc0bc2a7151f4ab652489e85253d5d0175 (diff)
downloadlinux-stericsson-3e619d04159be54b3daa0b7036b0ce9e067f4b5d.tar.gz
USB: EHCI: fix bug in scheduling periodic split transfers
This patch (as1654) fixes a very old bug in ehci-hcd, connected with scheduling of periodic split transfers. The calculations for full/low-speed bus usage are all carried out after the correction for bit-stuffing has been applied, but the values in the max_tt_usecs array assume it hasn't been. The array should allow for allocation of up to 90% of the bus capacity, which is 900 us, not 780 us. The symptom caused by this bug is that any isochronous transfer to a full-speed device with a maxpacket size larger than about 980 bytes is always rejected with a -ENOSPC error. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/ehci-sched.c')
-rw-r--r--drivers/usb/host/ehci-sched.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 2b6917dc3996..b476daf49f6f 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -213,7 +213,7 @@ static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __hc32 mask)
}
static const unsigned char
-max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
+max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 125, 25 };
/* carryover low/fullspeed bandwidth that crosses uframe boundries */
static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])