From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: Regressions for older OMAP3503 silicon Date: Wed, 5 Oct 2011 11:59:16 -0700 Message-ID: <20111005185916.GB6324@atomide.com> References: <20111005162618.GA6324@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:26945 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933170Ab1JES7S (ORCPT ); Wed, 5 Oct 2011 14:59:18 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Steve Sakoman Cc: Dave Hylands , linux-omap@vger.kernel.org * Steve Sakoman [111005 10:46]: > On Wed, Oct 5, 2011 at 9:26 AM, Tony Lindgren wrote: > > * Dave Hylands [111004 23:41]: > > >> I then also had to modify drivers/mmc/card/block.c and initializing > >> disable_multi to 1 in the mmc_blk_issue_rw_rq function to get rid of > >> the following messages for every I/O request. > >> > >> mmcblk0: retrying using single block read > >> mmcblk0: retrying using single block read > >> mmcblk0: retrying using single block read > >> mmcblk0: retrying using single block read > >> > >> (since this revision of the silicon doesn't support multi-block MMC reads). > > > > ..but this one is usually a problem muxing the MMC data lines. > > > > Are you sure this revision only supports one data line? > > No, I think you misunderstood the issue! > > The issue is that multi-block mmc reads are broken and the code falls > back to single block reads but prints a warning each time. > > Looking for a definitive source for this errata with Google I find: > > "According to the TI docs, multiple block read transfer > does not work correctly in CPU revisions 2.1 and earlier (TI advisory > 2.1.1.128)." OK, thanks for correcting me. > So the correct fix is probably to use multi-block reads only on > revisions post 2.1. Or just permanently switch to single-block reads if the multi-block reads fail? Regards, Tony