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authorAlan Stern <stern@rowland.harvard.edu>2014-12-04 10:21:56 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-27 08:18:57 -0800
commit727cc57106e72d38ad5d3f0aefb374ef0091f144 (patch)
treef431c00934ca2dc08e42b3c8d32fb22303a57262
parent23c631c3dbe28d5f89e70c4da7b4313177a4dc40 (diff)
USB: EHCI: fix initialization bug in iso_stream_schedule()
commit 6d89252a998a695ecb0348fc2d717dc33d90cae9 upstream. Commit c3ee9b76aa93 (EHCI: improved logic for isochronous scheduling) introduced the idea of using ehci->last_iso_frame as the origin (or base) for the circular calculations involved in modifying the isochronous schedule. However, the new code it added used ehci->last_iso_frame before the value was properly initialized. This patch rectifies the mistake by moving the initialization lines earlier in iso_stream_schedule(). This fixes Bugzilla #72891. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Fixes: c3ee9b76aa93 Reported-by: Joe Bryant <tenminjoe@yahoo.com> Tested-by: Joe Bryant <tenminjoe@yahoo.com> Tested-by: Martin Long <martin@longhome.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/host/ehci-sched.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index e113fd73aeae..c399606f154e 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1581,6 +1581,10 @@ iso_stream_schedule (
else
next = (now + 2 + 7) & ~0x07; /* full frame cache */
+ /* If needed, initialize last_iso_frame so that this URB will be seen */
+ if (ehci->isoc_count == 0)
+ ehci->last_iso_frame = now >> 3;
+
/*
* Use ehci->last_iso_frame as the base. There can't be any
* TDs scheduled for earlier than that.
@@ -1671,10 +1675,6 @@ iso_stream_schedule (
urb->start_frame = start & (mod - 1);
if (!stream->highspeed)
urb->start_frame >>= 3;
-
- /* Make sure scan_isoc() sees these */
- if (ehci->isoc_count == 0)
- ehci->last_iso_frame = now >> 3;
return status;
fail: