Re: [PATCH] TODO FLAG_POINTTOPOINT => FLAG_WWAN? usbnet/cdc_ncm: mark ncm devices as "mobile broadband devices" with FLAG_WWAN

From: Valdis . Kletnieks
Date: Thu Jun 02 2011 - 20:58:45 EST


On Thu, 02 Jun 2011 17:35:31 CDT, Dan Williams said:
> On Thu, 2011-06-02 at 17:29 -0500, Dan Williams wrote:
> > On Wed, 2011-06-01 at 12:20 +0200, Alexey ORISHKO wrote:
> > > > -----Original Message-----
> > > > From: netdev-owner@xxxxxxxxxxxxxxx [mailto:netdev-
> > > > owner@xxxxxxxxxxxxxxx] On Behalf Of Stefan Metzmacher
> > > > Sent: Wednesday, June 01, 2011 12:09 PM
> > >
> > >
> > > > - .flags = FLAG_POINTTOPOINT | FLAG_NO_SETINT | FLAG_MULTI_PACKET,
> > > > + .flags = FLAG_WWAN | FLAG_NO_SETINT | FLAG_MULTI_PACKET,
> > >
> > > This patch will introduce incompatibility with already existing
> > > applications, which track usbX devices. As a result, end user
> > > application will stop working.

I'm interpreting this as "devices which currently often get named usbX by udev,
and currently have FLAG_POINTTOPOINT set". People are getting hung up
on the usbX part, not what the *real* problem is.

> A follow-on to this is that if you really care about specific devices,
> your application can use udev rules to "tag" specific interfaces based
> on USB VID/PID/GUID or other device attributes, and check for those tags
> in your program. Use udev (good) or netlink (good) or SIOCGIFCONF (bad)
> to enumerate the various network interfaces on the system and pick the

I think Alexey's point was that the patch will hose up programs that
currently do the netlink or SIOCGIFCONF thing and look for FLAG_POINTTOPOINT.

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