From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752488Ab3LSKwE (ORCPT ); Thu, 19 Dec 2013 05:52:04 -0500 Received: from mga01.intel.com ([192.55.52.88]:63716 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751825Ab3LSKwC (ORCPT ); Thu, 19 Dec 2013 05:52:02 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.95,512,1384329600"; d="scan'208";a="446895084" Message-ID: <1387450289.1871.240.camel@smile> Subject: Re: [PATCH] dma: dw: Add suspend and resume handling for PCI mode DW_DMAC. From: Andy Shevchenko To: Vinod Koul Cc: "Chew, Chiau Ee" , Viresh Kumar , Andy Shevchenko , "Williams, Dan J" , "dmaengine@vger.kernel.org" , "linux-kernel@vger.kernel.org" Date: Thu, 19 Dec 2013 12:51:29 +0200 In-Reply-To: <20131218154955.GF16227@intel.com> References: <1386684373-24753-1-git-send-email-chiau.ee.chew@intel.com> <20131210101025.GF29580@intel.com> <1386676582.1871.137.camel@smile> <604BF5F4C5D71041942BC7E84ED659EA01520785@PGSMSX103.gar.corp.intel.com> <20131218154955.GF16227@intel.com> Organization: Intel Finland Oy Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.8.5-2+b1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2013-12-18 at 21:19 +0530, Vinod Koul wrote: > On Mon, Dec 16, 2013 at 01:51:47PM +0530, Chew, Chiau Ee wrote: > > As mentioned by Andy, we are using *_noirq verion of suspend/resume PM > > callback whereby the callbacks would be executed after IRQ handlers have been > > disabled. If using SET_SYSTEM_SLEEP_PM_OPS, it would be the normal > > suspend/resume PM callback. Looking at the Desginware DMAC platform code > > (drivers/dma/dw/platform.c), it is using the *_noirq suspend/resume PM > > callback. Is it advisable to use the normal suspend/resume PM callback instead > > of *_noirq suspend/PM callback? > > i dont see a reason why we need the noirq versions Okay. I imagine the following use case. For example we have compiled in DMA driver (dw_dmac) along with, for example, SPI driver. System was scheduled to go sleep. An order of calling IIUC might be DMA first, then SPI (since they are not in parent / child relations). What was happened when SPI would like to do a DMA transfer and DMA is going to sleep? I'm trying to understand if this is a case. > > > How about SET_SYSTEM_SLEEP_PM_OPS instead? > > > > So, we are using *_noirq versions of the functions here. What happened when we switch to normal ones? Any side effects? -- Andy Shevchenko Intel Finland Oy