dwc_otg: pay attention to qh->interval when rescheduling periodic queues

A regression introduced in https://github.com/raspberrypi/linux/pull/3887
meant that if the newly scheduled transfer immediately returned data, and
the driver resubmitted a single URB after every transfer, then the effective
polling interval would end up being approx 1ms.

Use the larger of SCHEDULE_SLOP or the configured endpoint interval.

Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>

diff --git a/drivers/usb/host/dwc_otg/dwc_otg_hcd_queue.c b/drivers/usb/host/dwc_otg/dwc_otg_hcd_queue.c
index 4503af6..f51fad1 100644 (file)
--- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_queue.c
+++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_queue.c
@@ -691,7 +691,7 @@ int dwc_otg_hcd_qh_add(dwc_otg_hcd_t * hcd, dwc_otg_qh_t * qh)
        } else {
                /* If the QH wasn't in a schedule, then sched_frame is stale. */
                qh->sched_frame = dwc_frame_num_inc(dwc_otg_hcd_get_frame_number(hcd),
-                                                       SCHEDULE_SLOP);
+                                                   max_t(uint32_t, qh->interval, SCHEDULE_SLOP));
                status = schedule_periodic(hcd, qh);
                qh->start_split_frame = qh->sched_frame;
                if ( !hcd->periodic_qh_count ) {