From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulf Hansson Subject: Re: [PATCH V2 0/2] mmc: Minimize resume time for sd/mmc Date: Tue, 3 Jan 2012 16:24:34 +0100 Message-ID: <4F031DB2.7010808@stericsson.com> References: <1323875170-7103-1-git-send-email-ulf.hansson@stericsson.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from eu1sys200aog102.obsmtp.com ([207.126.144.113]:41979 "EHLO eu1sys200aog102.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753650Ab2ACPYy (ORCPT ); Tue, 3 Jan 2012 10:24:54 -0500 In-Reply-To: <1323875170-7103-1-git-send-email-ulf.hansson@stericsson.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Chris Ball Cc: Ulf HANSSON , "linux-mmc@vger.kernel.org" , Per FORLIN , Johan RUDHOLM , Lee Jones , vitalywool@gmail.com Hi Chris, I have received some great comments some Vitaly Wool around the patch 2 "mmc: Minimize resume-time by deferring resume". It would be interesting to hear if you or someone else has any thinking around these patches. Vitaly were mainly thinking of a pm_qos approach, which still is a bit unclear to me how to implement. Any suggestion would be great! :-) Regarding patch 1: mmc: block: Remove use of mmc_blk_set_blksize This patch could be discussed separately without patch 2. Do you want me to push this patch on it's own? BR Ulf Hansson Ulf HANSSON wrote: > Typically an sd/mmc card takes around 200 - 1100 ms to > initialize when the power to the card has been cut, which > is what happens during a suspend/resume sequence. > > All device's resume time adds up to the total kernel resume > time. Some use cases requires the kernel to be resumed fast, > to be able to meet deadlines. One use case example is WLAN > SOFT_AP, but there are certainly more. > > This patch serie deferres the resume for mmc/sd cards into > a delayed work to be able to respond quickly on the suspend > request. Earlier the blkdev were issuing a set_blksize as a > part of the blkdev resume, which right now is removed since > it is not needed. In future, if other block sizes than 512 > bytes is used, this needs to be re-implemented in a different > manner. > > A deferred resume feature has been discussed on the mmc-list > previously but did not end up in a final patch/solution. > > Ulf Hansson (2): > mmc: block: Remove use of mmc_blk_set_blksize > mmc: Minimize resume-time by deferring resume > > drivers/mmc/card/block.c | 35 +++++++++-------------------------- > drivers/mmc/core/core.c | 36 +++++++++++++++++++++++++++++++++++- > drivers/mmc/core/core.h | 1 + > drivers/mmc/core/host.c | 1 + > include/linux/mmc/host.h | 16 ++++++++++++++++ > 5 files changed, 62 insertions(+), 27 deletions(-) >