From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Ossman Subject: Re: [PATCH 1/4] [MMC] core SDIO suspend/resume support Date: Sun, 6 Sep 2009 16:17:41 +0200 Message-ID: <20090906161741.33a56583@mjolnir.ossman.eu> References: <1251916646-3537-1-git-send-email-nico@cam.org> <1251916646-3537-2-git-send-email-nico@cam.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; protocol="application/pgp-signature"; boundary="=_freyr.ossman.eu-25038-1252246664-0001-2" Return-path: Received: from 82-117-125-11.tcdsl.calypso.net ([82.117.125.11]:35475 "EHLO smtp.ossman.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754827AbZIFORm (ORCPT ); Sun, 6 Sep 2009 10:17:42 -0400 In-Reply-To: <1251916646-3537-2-git-send-email-nico@cam.org> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Nicolas Pitre Cc: linux-mmc@vger.kernel.org This is a MIME-formatted message. If you see this text it means that your E-mail software does not support MIME-formatted messages. --=_freyr.ossman.eu-25038-1252246664-0001-2 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 02 Sep 2009 14:37:23 -0400 Nicolas Pitre wrote: >=20 > When resuming, we make sure the same card is still inserted by comparing > the vendor and product IDs. If there is a mismatch, or if there is simply > no card anymore in the slot, then the previous card is "removed" and the > new card is detected. >=20 I know this is an area with a lot of differing views, but I see this as totally insufficient. Like storage cards, this card might have a non-volatile state that drivers and upper layers rely on being the same before and after suspend. (Then there's also the issue of e.g. having two "identical" wifi cards but with different MAC addresses). I think the right way to go is to retain enough power to the card for it to stay initialised and then poke it at resume to see if it is still running in the same state we left it. Rgds --=20 -- Pierre Ossman WARNING: This correspondence is being monitored by the Swedish government. Make sure your server uses encryption for SMTP traffic and consider using PGP for end-to-end encryption. --=_freyr.ossman.eu-25038-1252246664-0001-2 Content-Type: application/pgp-signature; name="signature.asc" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.12 (GNU/Linux) iEYEARECAAYFAkqjxIcACgkQ7b8eESbyJLj/XwCgu7ipf5MlySpqZUzMPz7wRb4A SvoAoOqo6uKXLhDzGjYzjRbzlFj+kcUT =Atd/ -----END PGP SIGNATURE----- --=_freyr.ossman.eu-25038-1252246664-0001-2--