From: Matthijs Kooijman <matthijs@xxxxxxxx>
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: Matthijs Kooijman <matthijs@xxxxxxxx>
[paulz@xxxxxxxxxxxx: fixed comment style and added a couple of NULL checks]
Signed-off-by: Paul Zimmerman <paulz@xxxxxxxxxxxx>
---
drivers/staging/dwc2/hcd_intr.c | 33 +++++++++++++++++++++++++++++----
1 file changed, 29 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/dwc2/hcd_intr.c b/drivers/staging/dwc2/hcd_intr.c
index 4b007ab..8b68df8 100644
--- a/drivers/staging/dwc2/hcd_intr.c
+++ b/drivers/staging/dwc2/hcd_intr.c
@@ -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);
@@ -1708,8 +1708,9 @@ 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);
- dev_dbg(hsotg->dev, "qtd->complete_split %d\n",
- qtd->complete_split);
+ if (qtd)
+ dev_dbg(hsotg->dev, "qtd->complete_split %d\n",
+ qtd->complete_split);
dev_warn(hsotg->dev,
"%s: no halt status, channel %d, ignoring interrupt\n",
__func__, chnum);
@@ -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,
--
1.8.2.rc0.16.g20a599e
--
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