[PATCH v3] usb: gadget: f_uac2: Fix incorrect increment of bNumEndpoints

[PATCH v3] usb: gadget: f_uac2: Fix incorrect increment of bNumEndpoints

[Prashanth K]

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.

 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

Re: [PATCH v3] usb: gadget: f_uac2: Fix incorrect increment of bNumEndpoints

[John Keeping]

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
>