From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754972AbaEIKdc (ORCPT ); Fri, 9 May 2014 06:33:32 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:39063 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752652AbaEIKdb (ORCPT ); Fri, 9 May 2014 06:33:31 -0400 Date: Fri, 9 May 2014 11:33:15 +0100 From: Mark Brown To: Mika Westerberg Cc: linux-kernel@vger.kernel.org, Eric Miao , Russell King , Haojian Zhuang , Chiau Ee Chew , Hock Leong Kweh Message-ID: <20140509103315.GJ12304@sirena.org.uk> References: <1399559431-2065-1-git-send-email-mika.westerberg@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="oHvWihI+f7iV74d0" Content-Disposition: inline In-Reply-To: <1399559431-2065-1-git-send-email-mika.westerberg@linux.intel.com> X-Cookie: You will be successful in your work. User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: 94.175.94.161 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH] spi/pxa2xx: Prevent DMA from transferring too many bytes X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --oHvWihI+f7iV74d0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, May 08, 2014 at 05:30:31PM +0300, Mika Westerberg wrote: > In case we are doing DMA transfer and the size of the buffer is not multiple > of 4 bytes the driver truncates that to 4-byte boundary and tries to handle > remaining bytes using PIO. ... > While investigating this it turned out that the DMA hardware doesn't even > have such limitation so we can solve this by dropping the code that tries > to handle unaligned bytes. Is this definitely the case for all of the IPs using this driver? It seems like something which might have been present in actual PXA implemenetations but got fixed in later revisons used with x86. Equally well the current code is clearly broken either way so I'm not sure that problems with older systems should be a barrier to merging the patch but it seems better to check. --oHvWihI+f7iV74d0 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJTbK7oAAoJELSic+t+oim9FMUP/jRlwTJTd0UsV/ppYjS0p3rc B0P2rYKrGLP1KMCA0NLjyA7JjAOgsAGmqC/e/9k8uAxqUYQTk+hVpsASOAM2uIjh OdXAHuU4nTqIBdTzBMwdaxiJx7y9LHCtbCVgEmkkfFbHtMFroXhXsqM3LmGzujZe GQK24PUL1feOQlbqfb87NKq100K8vdTiqXqFIM0CWvHjGRQAAgtLzEe/5erW047H HY2I3NN24xTmkGFFCDfhqkaeoJGCP3JTe4nOiKvF4iFCGzJ+iShB0yu9BB8EHEba rHG4JwQUh5uPYAUuQgpo2IK5WSyr9RJEh+kBGf6vyZrJ9XioLkqHZ6G2YrcWZCbR 2Up4mT7LzmZzajpoc0VWX+xkeM2MuBkfoarl/OpGM7NfEaw7CTDMboynESp5toLn igL85zJAwRZgTadnnX3c9o5Kd83Kplhb1TXKe5a7XYszqUFULjNWvheE/zotDjqE 1X6vuNaEbKvCxqtnvll78HL3ouhjuRPry7PMyi9gQszh1PBG1ehpLUat/AumJHXr 84GJlPcQzPNUgyuS3Fs57SQnCacOoUhkRaPX1VvQxgSm+nQA/l53PktLK4vdsm6R heNwu22tIQIgqEqzWmz/OkHSLU78BgxNYMBZThXTp6ui2ITyg3PKTpJ5k3PNeq3T f2ruHOJNzy5l75iqdgGX =xhCJ -----END PGP SIGNATURE----- --oHvWihI+f7iV74d0--