From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752663AbeD1FGD (ORCPT ); Sat, 28 Apr 2018 01:06:03 -0400 Received: from mga03.intel.com ([134.134.136.65]:62283 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751342AbeD1FGB (ORCPT ); Sat, 28 Apr 2018 01:06:01 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,337,1520924400"; d="scan'208";a="35277339" Date: Sat, 28 Apr 2018 10:40:43 +0530 From: Vinod Koul To: Lars-Peter Clausen Cc: Moritz Fischer , Linux Kernel Mailing List , dmaengine@vger.kernel.org, dan.j.williams@intel.com Subject: Re: [PATCH v2] dmaengine: axi-dmac: Request IRQ with IRQF_SHARED Message-ID: <20180428051043.GG6014@localhost> References: <20180426174000.12008-1-mdf@kernel.org> <20180427051115.GX6014@localhost> <748ffc14-de12-c11e-eb12-65c599fe5f4e@metafoo.de> <20180427070830.GC6014@localhost> <716956a2-a4f4-9cbd-8761-8db477f1dfc0@metafoo.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <716956a2-a4f4-9cbd-8761-8db477f1dfc0@metafoo.de> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 27, 2018 at 05:18:29PM +0200, Lars-Peter Clausen wrote: > On 04/27/2018 05:15 PM, Moritz Fischer wrote: > > Hi Vinod, > > > > On Fri, Apr 27, 2018 at 12:08 AM, Vinod Koul wrote: > >> On Fri, Apr 27, 2018 at 08:53:39AM +0200, Lars-Peter Clausen wrote: > >>> On 04/27/2018 07:11 AM, Vinod Koul wrote: > >>>> On Thu, Apr 26, 2018 at 10:40:00AM -0700, Moritz Fischer wrote: > >>>>> Request IRQ with IRQF_SHARED flag. This works since the interrupt > >>>>> handler already checks if there is an actual IRQ pending and returns > >>>>> IRQ_NONE otherwise. > >>>> > >>>> hmmm what are we trying to fix here? Is your device on a shared line or not? > >>> > >>> IRQF_SHARED does not mean that the IRQ is on a shared line. It means that > >>> the driver can handle it if the IRQ is on a shared line. Since the driver > >>> can handle it setting the flag is a good idea since this enables usecases > >>> where the line is shared. > >> > >> Yes that is correct indeed, but what is the motivation for the change. > >> > >> If you never expect this to be in shared environment why to do this? > >> Sorry but "it works" is not a good enough reason for this change, to enable > >> usecases where the line is shared is a good reason :) > > > > Remember, this is an FPGA soft core. I happen to have a design [1] where it > > is hooked up with multiple of them on one IRQ line, so to make this work, > > I need this change. > > I think what Vinod is asking for is a change to the commit message saying > that "this change enables the driver to be used with devices where the > interrupt line is shared". Correct, changelog need to reflect why a change was made, down the line people need to know the reasons, sometimes it might be even you.. -- ~Vinod