Re: [PATCH v2 01/22] usb: add OTG version number in usb_otg_descriptor

[Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>]

Hi,

On Mon, 8 Jun 2015 23:01:56 +0800
Li Jun <jun.li-KZfg59tc24xl57MIdRCFDg@public.gmane.org> wrote:

> From: Macpaul Lin <macpaul-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> OTG 2.0 introduces bcdOTG to identify the OTG and EH supplement release
> number with which the OTG device is compliant, so adds it for
> usb_otg_descriptor.
> 
> Signed-off-by: Macpaul Lin <macpaul-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Li Jun <jun.li-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> ---
>  include/uapi/linux/usb/ch9.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
> index aa33fd1..ce405fb 100644
> --- a/include/uapi/linux/usb/ch9.h
> +++ b/include/uapi/linux/usb/ch9.h
> @@ -665,13 +665,17 @@ struct usb_qualifier_descriptor {
>  
>  
>  /*-------------------------------------------------------------------------*/
> +struct bcdOTG {
> +	__le16 bcdOTG;
> +};
>  
> -/* USB_DT_OTG (from OTG 1.0a supplement) */
> +/* USB_DT_OTG */
>  struct usb_otg_descriptor {
>  	__u8  bLength;
>  	__u8  bDescriptorType;
>  
>  	__u8  bmAttributes;	/* support for HNP, SRP, etc */
> +	struct bcdOTG otg_rev[0];
>  } __attribute__ ((packed));

This change by itself breaks existing users that depend
on sizeof(struct usb_otg_descriptor) and are USB OTG v1.0 compliant.

For otg v1.0 length of otg descriptor is 3
for otg v2.0 it is 5.

>  
>  /* from usb_otg_descriptor.bmAttributes */

cheers,
-roger
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