Re: [PATCH/RFC 5/5] usb: Add support for streams alloc/dealloc to devio.c

Alan Stern
2011-06-16T15:20:49Z

On Thu, 16 Jun 2011, Tatyana Brokhman wrote:

> Allow user space applications such as LIBUSB, to request
> streams alloc/dealloc from HCD that implements XHCI.
>
> Signed-off-by: Amit Blay <ablay@qualcomm.com>
> Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>

...

> diff --git a/include/linux/usbdevice_fs.h b/include/linux/usbdevice_fs.h
> index 15591d2..133c216 100644
> --- a/include/linux/usbdevice_fs.h
> +++ b/include/linux/usbdevice_fs.h
> @@ -108,6 +108,7 @@ struct usbdevfs_urb {
> or 0 if none should be sent. */
> void __user *usercontext;
> struct usbdevfs_iso_packet_desc iso_frame_desc[0];
> + unsigned int stream_id;
> };
>
> /* ioctls for talking directly to drivers */
> @@ -165,6 +166,7 @@ struct usbdevfs_urb32 {
> compat_uint_t signr;
> compat_caddr_t usercontext; /* unused */
> struct usbdevfs_iso_packet_desc iso_frame_desc[0];
> + compat_uint_t stream_id;
> };

It would be nice if we could do this, but we can't. We are not allowed
to change an established ABI. Every copy of libusb would have to be
rebuilt.

Alan Stern