Date: Tue, 15 Mar 2016 00:04:30 +0000
From: Nicolas Saenz Julienne <nicolassaenzj@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: oliver@neukum.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] USB: cdc-acm: add support for Sagem Monetel ELC930
Message-ID: <20160315000429.GA9008@vian>
References: <1457826291-5204-1-git-send-email-nicolassaenzj@gmail.com>
 <20160313002729.GA4420@kroah.com>
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On Sat, Mar 12, 2016 at 04:27:29PM -0800, Greg KH wrote:
> On Sat, Mar 12, 2016 at 11:44:51PM +0000, Nicolas Saenz Julienne wrote:
> > Signed-off-by: Nicolas Saenz Julienne <nicolassaenzj@gmail.com>
> > ---
> >  drivers/usb/class/cdc-acm.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
> > index fa4e239..9831607 100644
> > --- a/drivers/usb/class/cdc-acm.c
> > +++ b/drivers/usb/class/cdc-acm.c
> > @@ -1681,6 +1681,9 @@ static const struct usb_device_id acm_ids[] = {
> >  	{ USB_DEVICE(0x079b, 0x000f), /* BT On-Air USB MODEM */
> >  	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
> >  	},
> > +	{ USB_DEVICE(0x079b, 0x0088), /* SAGEM Monetel ELC930 */
> > +	.driver_info = NO_UNION_NORMAL, /* has no union descriptor */
> > +	},
>
> Why is this needed?  Does the descriptors not properly set the class
> device?
>
> thanks,
>
> greg k-h

Hi,
the device is missing all the ACM specific "extra" info on it's interface
descriptor. Which seems be triggering the "Zero length descriptor references"
error during the probe function. Adding the NO_UNION_NORMAL quirk seems to solve
the issue.
As for the class device, it seems to be ok, CDC (0x2).

	Nicolas