Date:   Wed, 25 Jan 2023 17:40:16 +0000
From:   John Keeping <john@metanate.com>
To:     Prashanth K <quic_prashk@quicinc.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Pavel Hofman <pavel.hofman@ivitera.com>,
        Joe Perches <joe@perches.com>, Julian Scheel <julian@jusst.de>,
        Colin Ian King <colin.i.king@gmail.com>,
        Pratham Pratap <quic_ppratap@quicinc.com>,
        Jack Pham <quic_jackp@quicinc.com>, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] usb: gadget: f_uac2: Fix incorrect increment of
 bNumEndpoints
Message-ID: <Y9FpgKYmRR415dz9@donbot>
References: <1674631645-28888-1-git-send-email-quic_prashk@quicinc.com>
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On Wed, Jan 25, 2023 at 12:57:25PM +0530, Prashanth K wrote:
> From: Pratham Pratap <quic_ppratap@quicinc.com>
> 
> Currently connect/disconnect of USB cable calls afunc_bind and
> eventually increments the bNumEndpoints. Performing multiple
> plugin/plugout will increment bNumEndpoints incorrectly, and on
> the next plug-in it leads to invalid configuration of descriptor
> and hence enumeration fails.
> 
> Fix this by resetting the value of bNumEndpoints to 1 on every
> afunc_bind call.
> 
> Fixes: 40c73b30546e ("usb: gadget: f_uac2: add adaptive sync support for capture")
> Signed-off-by: Pratham Pratap <quic_ppratap@quicinc.com>
> Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
> ---
> v3: Added Fixes tag.

Reviewed-by: John Keeping <john@metanate.com>

Is there a similar problem for std_ac_if_desc.bNumEndpoints ?  That
looks like it should be zero when no controls are enabled.

>  drivers/usb/gadget/function/f_uac2.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
> index 08726e4..0219cd7 100644
> --- a/drivers/usb/gadget/function/f_uac2.c
> +++ b/drivers/usb/gadget/function/f_uac2.c
> @@ -1142,6 +1142,7 @@ afunc_bind(struct usb_configuration *cfg, struct usb_function *fn)
>  		}
>  		std_as_out_if0_desc.bInterfaceNumber = ret;
>  		std_as_out_if1_desc.bInterfaceNumber = ret;
> +		std_as_out_if1_desc.bNumEndpoints = 1;
>  		uac2->as_out_intf = ret;
>  		uac2->as_out_alt = 0;
>  
> -- 
> 2.7.4
>