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From: Felipe Balbi <>
To: Wesley Cheng <>
Subject: Re: [PATCH v2] usb: dwc3: gadget: Avoid runtime resume if disabling pullup
Date: Wed, 04 Aug 2021 13:41:02 +0300	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Wesley Cheng <> writes:

> If the device is already in the runtime suspended state, any call to
> the pullup routine will issue a runtime resume on the DWC3 core
> device.  If the USB gadget is disabling the pullup, then avoid having
> to issue a runtime resume, as DWC3 gadget has already been
> halted/stopped.
> This fixes an issue where the following condition occurs:
> usb_gadget_remove_driver()
> -->usb_gadget_disconnect()
>  -->dwc3_gadget_pullup(0)
>   -->pm_runtime_get_sync() -> ret = 0
>   -->pm_runtime_put() [async]
> -->usb_gadget_udc_stop()
>  -->dwc3_gadget_stop()
>   -->dwc->gadget_driver = NULL
> ...
> dwc3_suspend_common()
> -->dwc3_gadget_suspend()
>  -->DWC3 halt/stop routine skipped, driver_data == NULL
> This leads to a situation where the DWC3 gadget is not properly
> stopped, as the runtime resume would have re-enabled EP0 and event
> interrupts, and since we avoided the DWC3 gadget suspend, these
> resources were never disabled.
> Fixes: 77adb8bdf422 ("usb: dwc3: gadget: Allow runtime suspend if UDC unbinded")
> Signed-off-by: Wesley Cheng <>

Acked-by: Felipe Balbi <>


      reply	other threads:[~2021-08-04 10:42 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-04  6:24 Wesley Cheng
2021-08-04 10:41 ` Felipe Balbi [this message]

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