From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcel Holtmann Subject: Re: [PATCH] allow setting wiphy.perm_addr after driver probe Date: Mon, 11 Aug 2014 15:41:38 -0700 Message-ID: <28066DB2-9EA9-4748-9C89-D3FBD3EC51F5@holtmann.org> References: <1407780269.28221.63.camel@chimera> <54DF22CF-59D7-4633-A625-896F58C26A64@holtmann.org> <1407789645.28221.68.camel@chimera> <37210DB5-2911-4FA3-9299-7701C5003945@holtmann.org> <1407791075.28221.74.camel@chimera> Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Cc: "John W. Linville" , "linux-wireless@vger.kernel.org Wireless" , Johannes Berg , "David S. Miller" , Network Development , linux-kernel@vger.kernel.org To: Daniel Gimpelevich Return-path: In-Reply-To: <1407791075.28221.74.camel@chimera> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hi Daniel, >> The initial wlan0 can be removed as every other netdev attached to the >> wiphy. It can also be as easily re-created. >> >> Since the wiphy does not have a valid MAC address, my proposal here >> would be to just not create the wlan0 in the first place. This means >> that the wiphy can be still discovered via nl80211. > > I repeat, currently wlan0 is *not* created. what kind of hardware are you actually using here? >> It also means that the wlan0 netdev needs to be created by userspace >> now. And a valid NL80211_ATTR_MAC be provided. Similar to what is >> already done for P2P devices at the moment. That should just solve the >> problem. > > The creation of wlan0 already comes from userspace, but the PHY has its > own MAC. > >> We really do not want to announce a netdev when registering the wiphy >> device and then having to mess with its MAC address via sysfs somehow. >> This all needs to be properly reflected over RTNL. >> > Again, no netdev is announced. There just isn't a way to set the MAC of > the wiphy device itself. > > How about this: What if the driver were to leave the MAC at all zeros > initially, and sysfs could set that if and only if it's all zeros at the > time? Internally it might do that, but I do not see it exposing the NL80211_ATTR_MAC when you get the attributes for wiphy. So I am still saying that when you do NL80211_CMD_NEW_INTERFACE allow providing NL80211_ATTR_MAC to set the MAC address to be used. It might be useful that the wiphy exposes an attribute saying that it does not have a default MAC address, but that should be it. I do not like these magic 00:00:00:00:00:00 games. As I mentioned earlier, in Bluetooth we just deal with allowing the driver to set a flag that it does not have a valid address. And then the core takes care of dealing with it. Regards Marcel