Re: [Qemu-devel] [PATCH 3/3] USB serial device support

[Pantelis Koukousoulas <pktoss@gmail.com>]

On Mon, May 18, 2009 at 6:00 PM, Jason Wessel
<jason.wessel@windriver.com> wrote:
> Add in a workaround to allow the usb serial devices to work with the
> usb pass through mechanism.  The ioctl() to request an alternate
> interface will always return < 0 for a usb-serial device based on the
> kernel driver.  This means there is no alternate interface end point.
>
> This was fully tested with a pl2303 usb serial device.
>
> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
> ---
>  usb-linux.c |    3 +--
>  1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/usb-linux.c b/usb-linux.c
> index 70d7a1c..67e4acd 100644
> --- a/usb-linux.c
> +++ b/usb-linux.c
> @@ -833,8 +833,7 @@ static int usb_linux_update_endp_table(USBHostDevice *s)
>
>         ret = ioctl(s->fd, USBDEVFS_CONTROL, &ct);
>         if (ret < 0) {
> -            perror("usb_linux_update_endp_table");
> -            return 1;
> +            alt_interface = interface;
>         }
>
>         /* the current interface descriptor is the active interface
> --
> 1.6.3.1.9.g95405b

+1 for this patch.
I 've tested it with my UPS (usb-serial essentially), a usb-serial adaptor
but even my konig gamepad doesn't work without it.

tested-by: Pantelis Koukousoulas <pktoss@gmail.com>