Message-ID: <1352715850.9525.17.camel@jlt4.sipsolutions.net> (sfid-20121112_112339_362932_953D656C)
Subject: Re: 60 GHz interface types (was: [PATCH v5 1/2] wireless: Driver
 for 60GHz card wil6210)
From: Johannes Berg <johannes@sipsolutions.net>
To: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Cc: "John W . Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org,
	"Luis R . Rodriguez" <rodrigue@qca.qualcomm.com>, j@w1.fi
Date: Mon, 12 Nov 2012 11:24:10 +0100
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On Mon, 2012-11-12 at 11:15 +0100, Johannes Berg wrote:

> > I suppose we can have MAC stuff in the kernel as-is, and at least at the 
> > beginning try to handle multi-band entirely in the supplicant.
> 
> But it does raise the question of what happens if a single device
> supports both 2.4 and 60 GHz, or maybe all three of 2.4, 5 and 60 GHz.
> 
> If that would be on a single wiphy, I think we might run into issues
> with re-using the interface types?

Let me elaborate on this. Lets say we have a hypothetical device that
supports

 2.4 GHz - client mode
 60 GHz  - AP and PCP mode

Yes, that would be pretty stupid, but let's say it exists, and even
worse than that, it only supports 2.4 GHz *or* 60 GHz, not both at the
same time (1).

Now how do you express its capabilities? Obviously it has both 2.4 and
60 GHz channels, and the list of interface types it supports would be
client, AP, PCP -- however there's no way to tell which it supports on
which bands.

Yes, this is a contrived example, but are you sure it won't exist? The
sticking point is the fact that this device only has a single MAC that
handles both 2.4 and 60 GHz, as it is usually the case for 2.4 and 5
GHz, but then the capabilities are the same, since things *are* the
same. Evidently though, a 2.4 GHz client and 60 GHz client are
different.

johannes


(1) If it did support both at the same time, it would register two wiphy
structs with cfg80211.