From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH] MMC Agressive clocking framework v6 Date: Mon, 01 Nov 2010 11:27:49 +0000 Message-ID: <4CCEA435.9030402@csr.com> References: <1288383487-29860-1-git-send-email-linus.walleij@stericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from queue01.mail.zen.net.uk ([212.23.3.234]:59448 "EHLO queue01.mail.zen.net.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754966Ab0KALsP (ORCPT ); Mon, 1 Nov 2010 07:48:15 -0400 In-Reply-To: <1288383487-29860-1-git-send-email-linus.walleij@stericsson.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Linus Walleij Cc: linux-mmc@vger.kernel.org, Ghorai Sukumar , Chris Ball , Nicolas Pitre , Adrian Hunter On 29/10/2010 21:18, Linus Walleij wrote: > This patch modifies the MMC core code to optionally call the > set_ios() operation on the driver with the clock frequency set > to 0 (gate) after a grace period of at least 8 MCLK cycles, then > restore it (ungate) before any new request. This gives > the driver the option to shut down the MCI clock to the MMC/SD > card when the clock frequency is 0, i.e. the core has stated > that the MCI clock does not need to be generated. With SDIO cards, 1 bit mode needs to be set on the controller otherwise many controllers cannot detect card interrupts. Also some v2.00 SDIO cards in 4-bit mode will not generate card interrupts unless they are clocked (the spec v2.00 doesn't require them to be able to but v3.00 does). I would suggest a white list of v2.00 cards that can generate interrupts asynchronousy. David