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Message-ID: <03bb678a-cbfa-bd04-1c69-8ee5109832e5@foss.st.com>
Date:   Thu, 10 Feb 2022 18:21:34 +0100
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Subject: Re: [PATCH] usb: dwc2: drd: fix soft connect when gadget is
 unconfigured
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To:     Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
        <hminas@synopsys.com>, <gregkh@linuxfoundation.org>
CC:     <linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <alexandre.torgue@foss.st.com>
References: <1644423353-17859-1-git-send-email-fabrice.gasnier@foss.st.com>
From:   Amelie DELAUNAY <amelie.delaunay@foss.st.com>
In-Reply-To: <1644423353-17859-1-git-send-email-fabrice.gasnier@foss.st.com>
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On 2/9/22 17:15, Fabrice Gasnier wrote:
> When the gadget driver hasn't been (yet) configured, and the cable is
> connected to a HOST, the SFTDISCON gets cleared unconditionally, so the
> HOST tries to enumerate it.
> At the host side, this can result in a stuck USB port or worse. When
> getting lucky, some dmesg can be observed at the host side:
>   new high-speed USB device number ...
>   device descriptor read/64, error -110
> 
> Fix it in drd, by checking the enabled flag before calling
> dwc2_hsotg_core_connect(). It will be called later, once configured,
> by the normal flow:
> - udc_bind_to_driver
>   - usb_gadget_connect
>     - dwc2_hsotg_pullup
>       - dwc2_hsotg_core_connect
> 
> Fixes: 17f934024e84 ("usb: dwc2: override PHY input signals with usb role switch support")
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>

Thanks for your patch,

Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>

Regards,
Amelie

> ---
>   drivers/usb/dwc2/drd.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
> index 1b39c47..9b6d44d 100644
> --- a/drivers/usb/dwc2/drd.c
> +++ b/drivers/usb/dwc2/drd.c
> @@ -130,8 +130,10 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
>   		already = dwc2_ovr_avalid(hsotg, true);
>   	} else if (role == USB_ROLE_DEVICE) {
>   		already = dwc2_ovr_bvalid(hsotg, true);
> -		/* This clear DCTL.SFTDISCON bit */
> -		dwc2_hsotg_core_connect(hsotg);
> +		if (hsotg->enabled) {
> +			/* This clear DCTL.SFTDISCON bit */
> +			dwc2_hsotg_core_connect(hsotg);
> +		}
>   	} else {
>   		if (dwc2_is_device_mode(hsotg)) {
>   			if (!dwc2_ovr_bvalid(hsotg, false))