Commit 8509f2f4 authored by Matthijs Kooijman's avatar Matthijs Kooijman Committed by Greg Kroah-Hartman
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staging: dwc2: always release host channel after dequeueing 



Previously, when an active urb was dequeued, its host channel would
not always be released. There is some special handling for this in
dwc2_hc_chhltd_intr_dma, but when it was the last urb/qtd in its qh, a
safeguard in dwc2_hc_n_intr would short-circuit and prevent the regular
interrupt handlers from running, without releasing the channel.

This is easily triggered when using a 3G modem using the option driver.
Opening and closing any ttyUSBx device will eat up a host channel that
is forever unusable from that point on.

Signed-off-by: default avatarMatthijs Kooijman <matthijs@stdin.nl>
[paulz@synopsys.com: fixed comment style and added a couple of NULL checks]
Signed-off-by: default avatarPaul Zimmerman <paulz@synopsys.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 257f6580

drivers/staging/dwc2/hcd_intr.c

+29 −4
Original line number Diff line number Diff line
@@ -708,7 +708,7 @@ static void dwc2_release_channel(struct dwc2_hsotg *hsotg, 
		free_qtd = 1;

		break;

	case DWC2_HC_XFER_XACT_ERR:

		if (qtd->error_count >= 3) {

		if (qtd && qtd->error_count >= 3) {

			dev_vdbg(hsotg->dev,

				 "  Complete URB with transaction error\n");

			free_qtd = 1;
@@ -729,7 +729,7 @@ static void dwc2_release_channel(struct dwc2_hsotg *hsotg, 
	case DWC2_HC_XFER_PERIODIC_INCOMPLETE:

		dev_vdbg(hsotg->dev, "  Complete URB with I/O error\n");

		free_qtd = 1;

		if (qtd->urb) {

		if (qtd && qtd->urb) {

			qtd->urb->status = -EIO;

			dwc2_host_complete(hsotg, qtd->urb->priv, qtd->urb,

					   -EIO);
@@ -1708,6 +1708,7 @@ static bool dwc2_halt_status_ok(struct dwc2_hsotg *hsotg, 
		dev_dbg(hsotg->dev,

			"hcint 0x%08x, hcintmsk 0x%08x, hcsplt 0x%08x,\n",

			chan->hcint, hcintmsk, hcsplt);

		if (qtd)

			dev_dbg(hsotg->dev, "qtd->complete_split %d\n",

				qtd->complete_split);

		dev_warn(hsotg->dev,
@@ -1937,7 +1938,31 @@ static void dwc2_hc_n_intr(struct dwc2_hsotg *hsotg, int chnum) 
	chan->hcint = hcint;

	hcint &= hcintmsk;



	/*

	 * If the channel was halted due to a dequeue, the qtd list might

	 * be empty or at least the first entry will not be the active qtd.

	 * In this case, take a shortcut and just release the channel.

	 */

	if (chan->halt_status == DWC2_HC_XFER_URB_DEQUEUE) {

		/*

		 * If the channel was halted, this should be the only

		 * interrupt unmasked

		 */

		WARN_ON(hcint != HCINTMSK_CHHLTD);

		if (hsotg->core_params->dma_desc_enable > 0)

			dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum,

						    chan->halt_status);

		else

			dwc2_release_channel(hsotg, chan, NULL,

					     chan->halt_status);

		return;

	}



	if (list_empty(&chan->qh->qtd_list)) {

		/*

		 * TODO: Will this ever happen with the

		 * DWC2_HC_XFER_URB_DEQUEUE handling above?

		 */

		dev_dbg(hsotg->dev, "## no QTD queued for channel %d ##\n",

			chnum);

		dev_dbg(hsotg->dev,