Re: [PATCH] USB: accept 1-byte Device Status replies

> From: Alan Stern <[email protected]>
>
> Some devices have a bug which causes them to send a 1-byte reply to
> Get-Device-Status requests instead of 2 bytes as required by the
> spec.  This doesn't play well with autosuspend, since we look for a
> valid status reply to make sure the device is still present when it
> resumes.  Without both bytes, we assume the device has been
> disconnected.
>
> Lack of the second byte shouldn't matter much, since the spec requires
> it always to be equal to 0.  Hence this patch (as959) causes
> finish_port_resume() to accept a 1-byte reply as valid.

ACK.  I've certainly been tempted to return single bytes there 
on occasion. ;)


> Signed-off-by: Alan Stern <[email protected]>
>
> ---
>
> Index: usb-2.6/drivers/usb/core/hub.c
> ===================================================================
> --- usb-2.6.orig/drivers/usb/core/hub.c
> +++ usb-2.6/drivers/usb/core/hub.c
> @@ -1764,9 +1764,10 @@ static int finish_port_resume(struct usb
>  	 * and device drivers will know about any resume quirks.
>  	 */
>  	if (status == 0) {
> +		devstatus = 0;
>  		status = usb_get_status(udev, USB_RECIP_DEVICE, 0, &devstatus);
>  		if (status >= 0)
> -			status = (status == 2 ? 0 : -ENODEV);
> +			status = (status > 0 ? 0 : -ENODEV);
>  	}
>  
>  	if (status) {
>
>

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