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;
spin_lock_irqsave(&dwc->lock, flags);
dwc3_disconnect_gadget(dwc);
@@ -4686,6 +4695,22 @@ int dwc3_gadget_suspend(struct dwc3 *dwc)
spin_unlock_irqrestore(&dwc->lock, flags);
return 0;
+
+err1:
+ /*
+ * 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);
+
+ ret = dwc3_gadget_run_stop(dwc, true, false);
+
+err0:
+ dev_info(dwc->dev, "%s error %d\n", __func__, ret);
+ return ret;
}
int dwc3_gadget_resume(struct dwc3 *dwc)
@@ -4695,6 +4720,15 @@ int dwc3_gadget_resume(struct dwc3 *dwc)
if (!dwc->gadget_driver || !dwc->softconnect)
return 0;
+ /*
+ * 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);
+
ret = __dwc3_gadget_start(dwc);
if (ret < 0)
goto err0;
--
cheers,
-roger
