From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulf Hansson Subject: Re: [PATCH] mmc: core: Prevent too long response times for suspend Date: Mon, 17 Oct 2011 11:51:00 +0200 Message-ID: <4E9BFA84.1040709@stericsson.com> References: <1318514638-32452-1-git-send-email-ulf.hansson@stericsson.com> <4f62290baad48cd8655f3f82f7b162b9.squirrel@www.codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from eu1sys200aog101.obsmtp.com ([207.126.144.111]:56193 "EHLO eu1sys200aog101.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751720Ab1JQJwH (ORCPT ); Mon, 17 Oct 2011 05:52:07 -0400 In-Reply-To: <4f62290baad48cd8655f3f82f7b162b9.squirrel@www.codeaurora.org> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Sujit Reddy Thumma Cc: "linux-mmc@vger.kernel.org" , Chris Ball , Per FORLIN , Lee Jones > > Why would there be pending requests while host is suspending? Is the > kernel framework not handling sync before going to suspend? However, the > mmc_blk_suspend() would be called before the host driver suspends (as all > the driver suspend routines are serialized) which means it stops block > layer to queue more I/O requests well before the host driver start > suspend. Does this sequence break in your case? I have observed this issue for different cases (one case was logging to eMMC). The idea is simply that we would like to be sure that we do not wait "forever", no matter if the "upper layers" misbehaved in the suspend sequence. > > Your concern seems to be valid for SDIO case, but again the function > driver must be intelligent enough to return -EBUSY as it knows that it had > posted a request to MMC. > For SDIO, should we really assume that function driver has implemented a suspend function and moreover that it actually always behaves as we expect? Br Ulf Hansson