Commit 5b145a90 authored by P33M's avatar P33M Committed by popcornmix
Browse files

dwc_otg: fix NAK holdoff and allow on split transactions only 

This corrects a bug where if a single active non-periodic endpoint
had at least one transaction in its qh, on frnum == MAX_FRNUM the qh
would get skipped and never get queued again. This would result in
a silent device until error detection (automatic or otherwise) would
either reset the device or flush and requeue the URBs.

Additionally the NAK holdoff was enabled for all transactions - this
would potentially stall a HS endpoint for 1ms if a previous error state
enabled this interrupt and the next response was a NAK. Fix so that
only split transactions get held off.
parent 204eb9e7

drivers/usb/host/dwc_otg/dwc_otg_hcd.c

+18 −10
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ 
#include "dwc_otg_hcd.h"

#include "dwc_otg_regs.h"



extern bool microframe_schedule;

extern bool microframe_schedule, nak_holdoff_enable;



//#define DEBUG_HOST_CHANNELS

#ifdef DEBUG_HOST_CHANNELS
@@ -1349,18 +1349,26 @@ dwc_otg_transaction_type_e dwc_otg_hcd_select_transactions(dwc_otg_hcd_t * hcd) 


		/*

		 * Check to see if this is a NAK'd retransmit, in which case ignore for retransmission

		 * we hold off on bulk retransmissions to reduce NAK interrupt overhead for

		 * we hold off on bulk retransmissions to reduce NAK interrupt overhead for full-speed

		 * cheeky devices that just hold off using NAKs

		 */

		if (dwc_full_frame_num(qh->nak_frame) == dwc_full_frame_num(dwc_otg_hcd_get_frame_number(hcd))) {

			// Make fiq interrupt run on next frame (i.e. 8 uframes)

		if (nak_holdoff_enable && qh->do_split) {

			if (qh->nak_frame != 0xffff &&

				dwc_full_frame_num(qh->nak_frame) ==

				dwc_full_frame_num(dwc_otg_hcd_get_frame_number(hcd))) {

				/*

				 * Revisit: Need to avoid trampling on periodic scheduling.

				 * Currently we are safe because g_np_count != g_np_sent whenever we hit this,

				 * but if this behaviour is changed then periodic endpoints will get a slower

				 * polling rate.

				 */

				g_next_sched_frame = ((qh->nak_frame + 8) & ~7) & DWC_HFNUM_MAX_FRNUM;

				qh_ptr = DWC_LIST_NEXT(qh_ptr);

				continue;

		}

		else

			} else {

				qh->nak_frame = 0xffff;



			}

		}

		if (microframe_schedule) {

				DWC_SPINLOCK_IRQSAVE(channel_lock, &flags);

				if (hcd->available_host_channels < 1) {