Re: [PATCH v2 15/16] wl1251: Add sysfs file address for setting permanent mac address

From: "Pali Rohár" <pali.rohar@gmail.com>
To: Dan Williams <dcbw@redhat.com>
Cc: Kalle Valo <kvalo@adurom.com>, Luciano Coelho <luca@coelho.fi>,
	"John W. Linville" <linville@tuxdriver.com>,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, freemangordon@abv.bg,
	aaro.koskinen@iki.fi, pavel@ucw.cz, sre@ring0.de,
	joni.lapilainen@gmail.com,
	Johannes Berg <johannes@sipsolutions.net>,
	Felipe Contreras <felipe.contreras@gmail.com>
Subject: Re: [PATCH v2 15/16] wl1251: Add sysfs file address for setting permanent mac address
Date: Tue, 10 Dec 2013 18:52:16 +0100	[thread overview]
Message-ID: <201312101852.17030@pali> (raw)
In-Reply-To: <1386697762.30202.6.camel@dcbw.foobar.com>

[-- Attachment #1: Type: Text/Plain, Size: 2054 bytes --]

On Tuesday 10 December 2013 18:49:22 Dan Williams wrote:
> On Tue, 2013-12-10 at 18:14 +0100, Pali Rohár wrote:
> > On Tuesday 10 December 2013 17:10:50 Pali Rohár wrote:
> > > On Tuesday 10 December 2013 16:49:23 Kalle Valo wrote:
> > > > Pali Rohár <pali.rohar@gmail.com> writes:
> > > > > Driver wl1251 generating mac address randomly at
> > > > > startup and there is no way to set permanent mac
> > > > > address via SET_IEEE80211_PERM_ADDR. This patch
> > > > > export sysfs file which can set permanent mac address
> > > > > by userspace helper program. Patch is needed for
> > > > > devices which do not store mac address in internal
> > > > > wl1251 eeprom.
> > > > > 
> > > > > Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
> > > > 
> > > > We have ioctl() command for setting the mac address.
> > > 
> > > Really? Is there ioctl for setting permanent mac address?
> > > Can you show me it?
> > 
> > Now I looked at it again and I did not found any ioctl for
> > it. There is only ioctl cmd for getting address, not
> > setting it.
> > 
> > #define SIOCETHTOOL 0x8946
> > 
> > /* Get permanent hardware address */
> > #define ETHTOOL_GPERMADDR 0x00000020
> 
> Yeah, because it's supposed to be permanent and unchanging. 
> Which means if there was an ioctl for it, that would be
> contrary to the purpose of a permanent MAC address.
> 
> I realize the N900 stores the WiFi MAC address completely
> differently than many other systems, and that's why this
> sysfs file was created.  I don't really have a great
> converged solution for that, other than what you've currently
> got, or perhaps adding SPERMADDR to ethtool.  One thing I
> *would* like though, is a restriction on the sysfs file such
> that if the permanent MAC is already set, it cannot be set
> again.  Otherwise the permanent MAC address isn't permanent
> at all.
> 
> Dan

Maybe another way could be to use request_firmware to load address 
from userspace... Or what do you think?

-- 
Pali Rohár
pali.rohar@gmail.com

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 198 bytes --]