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 <[email protected]> Fixes: c3ee9b76aa93 Reported-by: Joe Bryant <[email protected]> Tested-by: Joe Bryant <[email protected]> Tested-by: Martin Long <[email protected]> CC: <[email protected]> --- [as1769] drivers/usb/host/ehci-sched.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) Index: usb-3.18/drivers/usb/host/ehci-sched.c =================================================================== --- usb-3.18.orig/drivers/usb/host/ehci-sched.c +++ usb-3.18/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: -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
