From: Arnd Bergmann <arnd@arndb•de>
To: Alexey Orishko <alexey.orishko@gmail•com>
Cc: Ben Hutchings <bhutchings@solarflare•com>,
Steve Calfee <stevecalfee@gmail•com>,
Michal Nazarewicz <mnazarewicz@gmail•com>,
Randy Dunlap <rdunlap@xenotime•net>,
broonie@opensource•wolfsonmicro.com,
lkml <linux-kernel@vger•kernel.org>,
Nicolas Pitre <nicolas.pitre@linaro•org>,
Greg KH <greg@kroah•com>,
David Brownell <dbrownell@users•sourceforge.net>,
Alan Cox <alan@lxorguk•ukuu.org.uk>,
grant.likely@secretlab•ca,
Linux USB list <linux-usb@vger•kernel.org>,
andy.green@linaro•org, netdev@vger•kernel.org,
Benjamin Herrenschmidt <benh@kernel•crashing.org>,
roger.quadros@nokia•com,
Jaswinder Singh <jaswinder.singh@linaro•org>,
patches@linaro•org
Subject: Re: [RFC] usbnet: use eth%d name for known ethernet devices
Date: Fri, 25 Mar 2011 17:43:54 +0100 [thread overview]
Message-ID: <201103251743.54805.arnd@arndb.de> (raw)
In-Reply-To: <AANLkTikEJi7bg5GG3Ero_Poe9F6WiKo8rW+Y1KtxhQ4B@mail.gmail.com>
On Friday 25 March 2011, Alexey Orishko wrote:
> On Fri, Mar 25, 2011 at 12:57 PM, Arnd Bergmann <arnd@arndb•de> wrote:
> >
> > That would be a different way of looking at it. FLAG_POINTTOPOINT
> > describes what the device is (a USB cable connecting two hosts), and
> > that flag can be used for various things, where the only thing
> > we currently do is the netif naming.
> >
>
> For example, cdc_ether and cdc-ncm drivers can be used in different use cases:
> a) when device terminates the IP traffic
> or
> b) where device is a wireless router.
>
> In both cases ethernet frames are sent over usb cable and terminated
> in device (eth header stripped), so it is point-to-point link for ethernet, but
> looking from IP layer is not p2p link for case b).
>
> Please, explain, based on your idea, do we set this flag in both cases or not?
> Do you want to use the same netif name for both use cases described above?
>
Most importantly, I want to keep the current rules, so that nothing breaks
for existing users.
For cdc_ether and cdc-ncm devices, my patch always sets both FLAG_ETHER and
FLAG_POINTTOPOINT, because the driver has no way to find out which of the
two is actually there.
The usb-net core driver interprets this as meaning that it has to decide
for the name based on something else, and that happens to be the presence
of a globally assigned MAC address. I don't think that keying off the MAC
address here is a particularly good idea, but that's what the driver has
always done.
Arnd
prev parent reply other threads:[~2011-03-25 16:43 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4D79F068.2080009@linaro.org>
[not found] ` <201103231712.06184.arnd@arndb.de>
[not found] ` <20110323162251.GA9367@kroah.com>
2011-03-23 16:56 ` [RFC] usbnet: use eth%d name for known ethernet devices Arnd Bergmann
2011-03-23 17:04 ` Andy Green
2011-03-23 17:11 ` Arnd Bergmann
[not found] ` <201103231811.54290.arnd-r2nGTMty4D4@public.gmane.org>
2011-03-24 10:45 ` Andy Green
2011-03-23 17:13 ` Arnd Bergmann
2011-03-23 17:54 ` David Anders
2011-03-23 18:46 ` Greg KH
2011-03-23 19:35 ` Arnd Bergmann
[not found] ` <AANLkTim7hPfTv3gDYnh+jGxHBg0OvX=r1FKYoHnH7H_o@mail.gmail.com>
2011-03-23 19:57 ` Arnd Bergmann
2011-03-23 19:59 ` Randy Dunlap
2011-03-23 23:17 ` Michal Nazarewicz
2011-03-23 23:19 ` Randy Dunlap
2011-03-23 23:38 ` Steve Calfee
2011-03-24 0:01 ` Ben Hutchings
2011-03-24 13:13 ` Arnd Bergmann
2011-03-24 13:15 ` Arnd Bergmann
2011-03-24 13:44 ` Andy Green
[not found] ` <201103241415.45115.arnd-r2nGTMty4D4@public.gmane.org>
2011-03-24 13:56 ` Alan Stern
2011-03-24 17:20 ` Alexey Orishko
2011-03-25 11:57 ` Arnd Bergmann
2011-03-25 16:26 ` Alexey Orishko
2011-03-25 16:43 ` Arnd Bergmann [this message]
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