From: Alan Stern Date: Wed, 30 Jan 2013 21:36:40 +0000 (-0500) Subject: USB: EHCI: fix bug in scheduling periodic split transfers X-Git-Tag: v3.0.63~5 X-Git-Url: https://git.fsl.cs.sunysb.edu/?a=commitdiff_plain;h=f3f2759e76bfbd10f1612cf7f3d9d6e16fee1782;p=unionfs-2.6.39.y.git USB: EHCI: fix bug in scheduling periodic split transfers commit 3e619d04159be54b3daa0b7036b0ce9e067f4b5d upstream. 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 8949b239dec..53192f2e2c7 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -236,7 +236,7 @@ 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])