From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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@xxxxxxxxxxxxxxxxxxx> Fixes: c3ee9b76aa93 Reported-by: Joe Bryant <tenminjoe@xxxxxxxxx> Tested-by: Joe Bryant <tenminjoe@xxxxxxxxx> Tested-by: Martin Long <martin@xxxxxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- 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 85dd24ed97a6..8ecf164f0318 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -1384,6 +1384,10 @@ iso_stream_schedule ( now = ehci_read_frame_index(ehci) & (mod - 1); + /* If needed, initialize last_iso_frame so that this URB will be seen */ + if (ehci->isoc_count == 0) + ehci->last_iso_frame = now >> 3; + /* Typical case: reuse current schedule, stream is still active. * Hopefully there are no gaps from the host falling behind * (irq delays etc). If there are, the behavior depends on @@ -1493,10 +1497,6 @@ iso_stream_schedule ( urb->start_frame = stream->next_uframe; 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 0; fail: -- 2.2.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html