Message-ID: <1364395136.8388.9.camel@jlt4.sipsolutions.net> (sfid-20130327_153917_997724_A503CD8B)
Subject: Re: P2P support in brcmfmac
From: Johannes Berg <johannes@sipsolutions.net>
To: Arend van Spriel <arend@broadcom.com>
Cc: "John W. Linville" <linville@tuxdriver.com>,
	"John W. Linville" <linville@redhat.com>,
	David Spinadel <david.spinadel@intel.com>,
	linux-wireless@vger.kernel.org
Date: Wed, 27 Mar 2013 15:38:56 +0100
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On Wed, 2013-03-27 at 15:29 +0100, Arend van Spriel wrote:

> > As I understand it, brcmfmac currently supports having a P2P device
> > *netdev*, which is of (wireless) type STATION (presumably), which isn't
> > something we want to support (well, I don't anyway, it's difficult to
> > discover for applications).
> 
> It is a bit more subtle. After the merge window since 3.9-rc1 brcmfmac
> supports to have a P2P device *wireless dev* WITH a netdev associated as
> the old wpa_supplicant needed a network interface. 

Oh, funky, I had no idea.

> However, this
> interface is only created when the driver is loaded with a module
> parameter p2pon set to 1.

You could just remove the module parameter then?

> So brcmfmac announces P2P_DEVICE support in wiphy information. This will
> cause wpa_supplicant (with P2P device patches) to create a
> *wireless_dev* interface of P2P_DEVICE type.

Right, but this wouldn't work because you don't support the interface
creation, so it would really just be an attempt to create it?

> The interim patches went in 3.9-rc1 so they end up in 3.9 without
> nl80211 user-space support. I am now suggesting to add that nl80211
> user-space support for 3.9 as well. As you indicated you do not consider
> this as an exception to the bugfix rule, I will have to look what
> happens when the new wpa_supplicant (with P2P device patches) tries to
> use the 3.9-rc1 brcmfmac.

Or you could just remove the module parameter *and* advertisting the
P2P_DEVICE interface type, that would be a very small patch to "fix" the
API by disabling it for that kernel version. OTOH, I'm not sure if
that's a concern for you. For me, it wouldn't be a concern because we
mostly use compat-wireless anyway, but your situation might be
different.

johannes