From 6d89252a998a695ecb0348fc2d717dc33d90cae9 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Thu, 4 Dec 2014 10:21:56 -0500 Subject: [PATCH] USB: EHCI: fix initialization bug in iso_stream_schedule() 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 Fixes: c3ee9b76aa93 Reported-by: Joe Bryant Tested-by: Joe Bryant Tested-by: Martin Long CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-sched.c | 8 ++++---- 1 file 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: -- 2.20.1