From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH V2 00/15] mmc: host: Add facility to support re-tuning Date: Mon, 09 Feb 2015 10:43:12 +0200 Message-ID: <54D87320.6080104@intel.com> References: <1422522030-17793-1-git-send-email-adrian.hunter@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mga14.intel.com ([192.55.52.115]:21069 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760080AbbBIIpN (ORCPT ); Mon, 9 Feb 2015 03:45:13 -0500 In-Reply-To: <1422522030-17793-1-git-send-email-adrian.hunter@intel.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson , Chris Ball Cc: linux-mmc , Aaron Lu , Philip Rakity , Girish K S , Al Cooper , Arend van Spriel On 29/01/15 11:00, Adrian Hunter wrote: > Hi > > Here is V2 of some patches to move re-tuning support > out of sdhci and into the core, and add support for HS400 > re-tuning. > > Currently sdhci does re-tuning transparently by > calling sdhci_execute_tuning() from its ->request() > function. > > The problem with HS400 re-tuning is that it must be > done in HS200 mode. That means using switch commands > and making ios changes. That means it potentially > conflicts with other command sequences. The new > re-tuning support accomodates that, however it is > not strictly necessary because HS400 re-tuning > should only be needed after runtime suspend when > there would not be a conflict. > > Nevertheless, this approach has more structure > and potentially more flexibility. > > Changes in V2: > > Added support to the block driver for re-tuning > and retrying after a CRC error. The host driver > is left to decide when an error indicates re-tuning > is needed. The block driver will retry a data request > once if re-tuning is flagged as needed. > > SDIO drivers need not be aware of re-tuning because > retrying will anyway cause re-tuning when re-tuning > is flagged as needed. Nevertheless SDIO drivers could > use the need_retune flag to instigate a retry when > otherwise they might not have. Ulf, Arend, is this OK?