From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrey Borzenkov Subject: Re: [PATCH] Expose netdevice dev_id through sysfs Date: Sun, 20 Apr 2008 09:21:03 +0400 Message-ID: <200804200921.09072.arvidjaar@mail.ru> References: <1208171478.31695.58.camel@pmac.infradead.org> <1208176322.31695.73.camel@pmac.infradead.org> <20080419.183341.46125500.davem@davemloft.net> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1786829.yDRibfeeRA"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Cc: David Miller , dwmw2@infradead.org, kay.sievers@vrfy.org, md@linux.it, harald@redhat.com, netdev@vger.kernel.org, schwidefsky@de.ibm.com To: linux-hotplug@vger.kernel.org Return-path: In-Reply-To: <20080419.183341.46125500.davem@davemloft.net> Sender: linux-hotplug-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --nextPart1786829.yDRibfeeRA Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Sunday 20 April 2008, David Miller wrote: > We're trying to provide uniqueness amongst all devices in the system > that are using the same MAC address. >=20 > On a Sparc system, for example, ethernet chips driven by several > different drivers can end up with the same MAC address, as the > system IDPROM specified ethernet MAC is what will be used by > default. >=20 On Sparc system we also have global device tree which provides unique and persistent reference to every device. Solaris has no problems with having same MAC for all interfaces. > So we need some global scheme. And this dev_id value would need to be > persistent. As best as I can tell, such things aren't available. What is exactly wrong with using device topology path? This should exist on any system, it is unique and it is persistent. > Sure we could do something silly like use the device I/O physical > address, but that would defeat the whole purpose of making device > identification agnostic to I/O bus geography. I could move the > card to a different slot and it would have a different dev_id. >=20 Sure; a card in different slot *is* a different device. And when broken card is replaced in the same slot for all practical purposes it *is* the same device even if MAC has changed. Nobody makes cable labels like "card with MAC xxx"; every cable label has something like "shelf 2; PCI slot 3; port 1". --nextPart1786829.yDRibfeeRA Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEABECAAYFAkgK0sEACgkQR6LMutpd94xB6wCfRdsiPq27Tah12z5YKw9vmjvE V5cAmgJrRQzJPXLiQV15yIJe37WJSBA9 =GDW9 -----END PGP SIGNATURE----- --nextPart1786829.yDRibfeeRA--