PERFORCE change 161961 for review

[Andrew Thompson]

On Tue, May 12, 2009 at 06:39:53AM +0000, Hans Petter Selasky wrote:
> http://perforce.freebsd.org/chv.cgi?CH=161961
> 
> Change 161961 by hselasky at hselasky_laptop001 on 2009/05/12 06:38:57
> 
> 	
> 	USB CORE:
> 	 - Cancelled error code must be returned in special
> 	 case, else device drivers might end up in infinite loop.
> 	 - The special case code was introduced by a recent commit.
> 	
> 	Bug report by: Andrey <andrey.kosachenko at gmail.com>
> 
> Affected files ...
> 
> .. //depot/projects/usb/src/sys/dev/usb/usb_transfer.c#144 edit
> 
> Differences ...
> 
> ==== //depot/projects/usb/src/sys/dev/usb/usb_transfer.c#144 (text+ko) ====
> 
> @@ -1439,7 +1439,11 @@
>  	/* Check if the device is still alive */
>  	if (info->udev->state < USB_STATE_POWERED) {
>  		USB_BUS_LOCK(bus);
> -		usb2_transfer_done(xfer, USB_ERR_NOT_CONFIGURED);
> +		/*
> +		 * Must return cancelled error code else
> +		 * device drivers can hang.
> +		 */
> +		usb2_transfer_done(xfer, USB_ERR_CANCELLED);
>  		USB_BUS_UNLOCK(bus);
>  		return;
>  	}

I rather think this is a bug in the drivers, they blindly resubmit the
transfer without knowing if the error is restartable.


Andew