On Thu, Apr 27, 2023, Roger Quadros wrote:
> Hi,
>
> On 26/04/2023 23:01, Thinh Nguyen wrote:
> > Hi,
> >
> > On Wed, Apr 26, 2023, Roger Quadros wrote:
> >> Hi Thinh,
> >>
> >> On Linux kernel v6.3
> >> Test procedure:
> >>
> >> - modprobe g_zero
> >> - Connect to PC host
> >> - systemctl suspend
> >>
> >> A large delay of 3 seconds is observed. The delay comes from dwc3_gadget_suspend()->dwc3_gadget_run_stop() waiting for DWC3_DSTS_DEVCTRLHLT to be set.
> >> It returns -ETIMEDOUT.
> >>
> >> Are we missing something to do a clean stop during suspend?
> >>
> >> FYI. Unloading g_zero does not show this delay on stop.
> >>
> >> cheers,
> >> -roger
> >
> > When clearing run_stop bit and the controller doesn't halt, that usually
> > means there are active transfers/endpoints that aren't ended yet.
> >
> > The dwc3_gadget_suspend() doesn't properly do all the cleanup before
> > clearing the run_stop bit. I think you just need to call
> > dwc3_gadget_soft_disconnect() in dwc3_gadget_suspend() to fix this.
>
> That seems to do the trick.
> How does this look?
>
> -------------------------- drivers/usb/dwc3/gadget.c --------------------------
> @@ -4674,11 +4676,18 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
> int dwc3_gadget_suspend(struct dwc3 *dwc)
> {
> unsigned long flags;
> + int ret;
>
> - if (!dwc->gadget_driver)
> + if (!dwc->gadget_driver || !dwc->softconnect)
> return 0;
>
> - dwc3_gadget_run_stop(dwc, false, false);
> + ret = dwc3_gadget_soft_disconnect(dwc);
> + if (ret)
> + goto err0;
> +
> + ret = dwc3_gadget_run_stop(dwc, false, false);
> + if (ret)
> + goto err1;
>
We already clear run_stop in dwc3_gadget_soft_disconnect().
Can you try the following change (not tested):
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index c0ca4d12f95d..2996bcb4d53d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2699,6 +2699,21 @@ static int dwc3_gadget_soft_disconnect(struct dwc3 *dwc)
return ret;
}
+static int dwc3_gadget_soft_connect(struct dwc3 *dwc)
+{
+ /*
+ * In the Synopsys DWC_usb31 1.90a programming guide section
+ * 4.1.9, it specifies that for a reconnect after a
+ * device-initiated disconnect requires a core soft reset
+ * (DCTL.CSftRst) before enabling the run/stop bit.
+ */
+ dwc3_core_soft_reset(dwc);
+
+ dwc3_event_buffers_setup(dwc);
+ __dwc3_gadget_start(dwc);
+ return dwc3_gadget_run_stop(dwc, true);
+}
+
static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
{
struct dwc3 *dwc = gadget_to_dwc(g);
@@ -2737,21 +2752,10 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
synchronize_irq(dwc->irq_gadget);
- if (!is_on) {
+ if (!is_on)
ret = dwc3_gadget_soft_disconnect(dwc);
- } else {
- /*
- * In the Synopsys DWC_usb31 1.90a programming guide section
- * 4.1.9, it specifies that for a reconnect after a
- * device-initiated disconnect requires a core soft reset
- * (DCTL.CSftRst) before enabling the run/stop bit.
- */
- dwc3_core_soft_reset(dwc);
-
- dwc3_event_buffers_setup(dwc);
- __dwc3_gadget_start(dwc);
- ret = dwc3_gadget_run_stop(dwc, true);
- }
+ else
+ ret = dwc3_gadget_soft_connect(dwc);
pm_runtime_put(dwc->dev);
@@ -4655,42 +4659,39 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
int dwc3_gadget_suspend(struct dwc3 *dwc)
{
unsigned long flags;
+ int ret;
if (!dwc->gadget_driver)
return 0;
- dwc3_gadget_run_stop(dwc, false);
+ ret = dwc3_gadget_soft_disconnect(dwc);
+ if (ret)
+ goto err;
spin_lock_irqsave(&dwc->lock, flags);
dwc3_disconnect_gadget(dwc);
- __dwc3_gadget_stop(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);
return 0;
+
+err:
+ /*
+ * Attempt to reset the controller's state. Likely no
+ * communication can be established until the host
+ * performs a port reset.
+ */
+ if (dwc->softconnect)
+ dwc3_gadget_soft_connect(dwc);
+
+ return ret;
}
int dwc3_gadget_resume(struct dwc3 *dwc)
{
- int ret;
-
if (!dwc->gadget_driver || !dwc->softconnect)
return 0;
- ret = __dwc3_gadget_start(dwc);
- if (ret < 0)
- goto err0;
-
- ret = dwc3_gadget_run_stop(dwc, true);
- if (ret < 0)
- goto err1;
-
- return 0;
-
-err1:
- __dwc3_gadget_stop(dwc);
-
-err0:
- return ret;
+ return dwc3_gadget_soft_connect(dwc);
}
void dwc3_gadget_process_pending_events(struct dwc3 *dwc)
--
Thanks,
Thinh
