From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH 02/12] mmc: sd: add support for signal voltage switch procedure Date: Tue, 15 Feb 2011 11:16:27 +0100 Message-ID: <20110215101627.GC13934@pengutronix.de> References: <1297762510-2696-1-git-send-email-arindam.nath@amd.com> <1297762510-2696-3-git-send-email-arindam.nath@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:38288 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754174Ab1BOKQc convert rfc822-to-8bit (ORCPT ); Tue, 15 Feb 2011 05:16:32 -0500 Content-Disposition: inline In-Reply-To: <1297762510-2696-3-git-send-email-arindam.nath@amd.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Arindam Nath Cc: cjb@laptop.org, linux-mmc@vger.kernel.org, henry.su@amd.com, aaron.lu@amd.com, anath.amd@gmail.com On Tue, Feb 15, 2011 at 03:05:00PM +0530, Arindam Nath wrote: > Host Controller v3.00 adds another Capabilities register. We can > directly read this register without any version checking since the > new register bits will be considred as reserved in older controllers, > and will be read as 0. I so much wish you were right, but reality is different :( The i.MX35-processor, for example, has a custom watermark-register there. I could fix this by intercepting the read using io-accessors, but to minimize potential regressions on older controllers in general, I'd say the check for v3 might be justified? Regards, Wolfram -- Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ |