The following commit has been merged in the linux branch: commit 36f21329d217016f0f212f0752ae595b4a76754d Author: Sarah Sharp sarah.a.sharp@linux.intel.com Date: Fri Oct 9 12:28:41 2009 -0700

USB: ehci: Fix IST boundary checking interval math.

When the EHCI driver falls behind in its scheduling, the active stream's first empty microframe may be in the past with respect to the current microframe. The code attempts to move the starting microframe ("start") N number of microframes forward, where N is the interval of endpoint. However, stream->interval is a copy of the endpoint's bInterval, which is designated in frames for FS devices, and microframes for HS devices. Convert stream->interval to microframes before using it to move the starting microframe forward.

Acked-by: Alan Stern stern@rowland.harvard.edu Signed-off-by: Sarah Sharp sarah.a.sharp@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@suse.de

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 3efa59b..b25cdea 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1400,6 +1400,10 @@ iso_stream_schedule ( goto fail; }

+ period = urb->interval; + if (!stream->highspeed) + period <<= 3; + now = ehci_readl(ehci, &ehci->regs->frame_index) % mod;

/* when's the last uframe this urb could start? */ @@ -1417,8 +1421,8 @@ iso_stream_schedule (

/* Fell behind (by up to twice the slop amount)? */ if (start >= max - 2 * 8 * SCHEDULE_SLOP) - start += stream->interval * DIV_ROUND_UP( - max - start, stream->interval) - mod; + start += period * DIV_ROUND_UP( + max - start, period) - mod;

/* Tried to schedule too far into the future? */ if (unlikely((start + sched->span) >= max)) { @@ -1441,10 +1445,6 @@ iso_stream_schedule (

/* NOTE: assumes URB_ISO_ASAP, to limit complexity/bugs */

- period = urb->interval; - if (!stream->highspeed) - period <<= 3; - /* find a uframe slot with enough bandwidth */ for (; start < (stream->next_uframe + period); start++) { int enough_space;