Re: libusb broken on 2.6.28 x86_64 ?

[Alan Stern]

On Fri, 2 Jan 2009, Mark Lord wrote:

> Greg KH wrote:
> ..
> > Hm, care to run 'git bisect'?
> ..
> 
> No, thanks.  But the number of USB core changes in 2.6.28 is rather small,
> so I just ended up looking at each of them in more detail.
> 
> This patch, below, FIXES it for me, by undoing a change from 2.6.28.
> 
> Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
> 
> --- old/drivers/usb/core/driver.c	2008-12-24 18:26:37.000000000 -0500
> +++ linux/drivers/usb/core/driver.c	2009-01-02 04:34:11.000000000 -0500
> @@ -279,9 +279,7 @@
>  	 * altsetting means creating new endpoint device entries).
>  	 * When either of these happens, defer the Set-Interface.
>  	 */
> -	if (intf->cur_altsetting->desc.bAlternateSetting == 0)
> -		;	/* Already in altsetting 0 so skip Set-Interface */
> -	else if (!error && intf->dev.power.status == DPM_ON)
> +	if (!error && intf->dev.power.status == DPM_ON)
>  		usb_set_interface(udev, intf->altsetting[0].
>  				desc.bInterfaceNumber, 0);
>  	else

For a proper fix, see

	http://bugzilla.kernel.org/show_bug.cgi?id=12301#c13

A corresponding patch has been posted to linux-usb here:

	http://marc.info/?l=linux-usb&m=123074111001861&w=2

I have no idea what's going on with the 64-bit vs. 32-bit stuff, 
though.

Alan Stern

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