From: Michael Grzeschik <m.grzeschik@pengutronix.de>
To: Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Michael Grzeschik <m.grzeschik@pengutronix.de>
Subject: [PATCH v2] usb: dwc3: gadget: check drained isoc ep
Date: Tue, 02 Apr 2024 23:51:49 +0200 [thread overview]
Message-ID: <20240307-dwc3-gadget-complete-irq-v2-1-8c5e9b35f7b9@pengutronix.de> (raw)
To avoid a potential underrun of an currently drained transfer
we add a check for that scenario in the dwc3_gadget_endpoint_trbs_complete
function. In the case of an empty trb ring, we call the stop_transfer
cmd and avoid the underrun to occur.
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
Changes in v2:
- dropped patch "usb: dwc3: gadget: reclaim the whole started list when request was missed"
- fixed patch "usb: dwc3: gadget: check drained isoc ep"
- dropped patch "usb: dwc3: gadget: check the whole started queue for missed requests in complete"
- Link to v1: https://lore.kernel.org/r/20240307-dwc3-gadget-complete-irq-v1-0-4fe9ac0ba2b7@pengutronix.de
---
drivers/usb/dwc3/gadget.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 4df2661f66751..3e9c67799259a 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3582,13 +3582,26 @@ static bool dwc3_gadget_endpoint_trbs_complete(struct dwc3_ep *dep,
if (!dep->endpoint.desc)
return no_started_trb;
- if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
- list_empty(&dep->started_list) &&
- (list_empty(&dep->pending_list) || status == -EXDEV))
- dwc3_stop_active_transfer(dep, true, true);
- else if (dwc3_gadget_ep_should_continue(dep))
+ if (usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
+ /* It is possible that the interrupt thread was delayed
+ * by scheduling in the system, and therefor the HW has
+ * already run dry. In that case the last trb in the
+ * queue is already handled by the hw. By checking the
+ * HWO bit we know to restart the whole transfer. The
+ * condition to appear is more likely if not every req
+ * has the IOC bit set and therefor does not trigger the
+ * interrupt thread frequently.
+ */
+ struct dwc3_trb *trb = dwc3_ep_prev_trb(dep, dep->trb_enqueue);
+ unsigned int transfer_in_flight = trb->ctrl & DWC3_TRB_CTRL_HWO;
+
+ if ((list_empty(&dep->started_list) || !transfer_in_flight) &&
+ (list_empty(&dep->pending_list) || status == -EXDEV))
+ dwc3_stop_active_transfer(dep, true, true);
+ } else if (dwc3_gadget_ep_should_continue(dep)) {
if (__dwc3_gadget_kick_transfer(dep) == 0)
no_started_trb = false;
+ }
out:
/*
---
base-commit: 5bab5dc780c9ed0c69fc2f828015532acf4a7848
change-id: 20240307-dwc3-gadget-complete-irq-1a8ffa347fd1
Best regards,
--
Michael Grzeschik <m.grzeschik@pengutronix.de>
next reply other threads:[~2024-04-02 21:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-02 21:51 Michael Grzeschik [this message]
2024-04-02 23:06 ` [PATCH v2] usb: dwc3: gadget: check drained isoc ep Thinh Nguyen
2024-04-02 23:18 ` Thinh Nguyen
2024-04-04 0:29 ` Thinh Nguyen
2024-04-23 13:37 ` Michael Grzeschik
2024-04-24 1:51 ` Thinh Nguyen
2024-05-04 23:44 ` Michael Grzeschik
2024-05-08 23:03 ` Thinh Nguyen
2024-05-08 23:53 ` Michael Grzeschik
2024-05-11 0:51 ` Thinh Nguyen
2024-05-12 21:33 ` Michael Grzeschik
2024-05-17 1:29 ` Thinh Nguyen
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