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Date:   Tue, 15 Feb 2022 15:04:20 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Cc:     hminas@synopsys.com, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        amelie.delaunay@foss.st.com, alexandre.torgue@foss.st.com
Subject: Re: [PATCH v2] usb: dwc2: drd: fix soft connect when gadget is
 unconfigured
Message-ID: <Yguy5OMW477VmMuv@kroah.com>
References: <1644923059-3619-1-git-send-email-fabrice.gasnier@foss.st.com>
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In-Reply-To: <1644923059-3619-1-git-send-email-fabrice.gasnier@foss.st.com>
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On Tue, Feb 15, 2022 at 12:04:19PM +0100, 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>
> ---
> Changes in v2:
> - Fix build error: 'struct dwc2_hsotg' has no member named 'enabled';
>   as reported by the kernel test robot.
>   https://lore.kernel.org/all/202202112236.AwoOTtHO-lkp@intel.com/
>   Add dwc2_is_device_enabled() macro to handle this.
> ---
>  drivers/usb/dwc2/core.h | 2 ++
>  drivers/usb/dwc2/drd.c  | 6 ++++--
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 8a63da3..8a7751b 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -1418,6 +1418,7 @@ void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
>  void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
>  int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
>  #define dwc2_is_device_connected(hsotg) (hsotg->connected)
> +#define dwc2_is_device_enabled(hsotg) ((hsotg)->enabled)

Why the extra ()?  dwc2_is_device_connected does not have it, so this
one probably should not either, right?

thanks,

greg k-h