From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v2] dmaengine: axi-dmac: Request IRQ with IRQF_SHARED From: Vinod Koul Message-Id: <20180427070830.GC6014@localhost> Date: Fri, 27 Apr 2018 12:38:30 +0530 To: Lars-Peter Clausen Cc: Moritz Fischer , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, dan.j.williams@intel.com List-ID: T24gRnJpLCBBcHIgMjcsIDIwMTggYXQgMDg6NTM6MzlBTSArMDIwMCwgTGFycy1QZXRlciBDbGF1 c2VuIHdyb3RlOgo+IE9uIDA0LzI3LzIwMTggMDc6MTEgQU0sIFZpbm9kIEtvdWwgd3JvdGU6Cj4g PiBPbiBUaHUsIEFwciAyNiwgMjAxOCBhdCAxMDo0MDowMEFNIC0wNzAwLCBNb3JpdHogRmlzY2hl ciB3cm90ZToKPiA+PiBSZXF1ZXN0IElSUSB3aXRoIElSUUZfU0hBUkVEIGZsYWcuIFRoaXMgd29y a3Mgc2luY2UgdGhlIGludGVycnVwdAo+ID4+IGhhbmRsZXIgYWxyZWFkeSBjaGVja3MgaWYgdGhl cmUgaXMgYW4gYWN0dWFsIElSUSBwZW5kaW5nIGFuZCByZXR1cm5zCj4gPj4gSVJRX05PTkUgb3Ro ZXJ3aXNlLgo+ID4gCj4gPiBobW1tIHdoYXQgYXJlIHdlIHRyeWluZyB0byBmaXggaGVyZT8gSXMg eW91ciBkZXZpY2Ugb24gYSBzaGFyZWQgbGluZSBvciBub3Q/Cj4gCj4gSVJRRl9TSEFSRUQgZG9l cyBub3QgbWVhbiB0aGF0IHRoZSBJUlEgaXMgb24gYSBzaGFyZWQgbGluZS4gSXQgbWVhbnMgdGhh dAo+IHRoZSBkcml2ZXIgY2FuIGhhbmRsZSBpdCBpZiB0aGUgSVJRIGlzIG9uIGEgc2hhcmVkIGxp bmUuIFNpbmNlIHRoZSBkcml2ZXIKPiBjYW4gaGFuZGxlIGl0IHNldHRpbmcgdGhlIGZsYWcgaXMg YSBnb29kIGlkZWEgc2luY2UgdGhpcyBlbmFibGVzIHVzZWNhc2VzCj4gd2hlcmUgdGhlIGxpbmUg aXMgc2hhcmVkLgoKWWVzIHRoYXQgaXMgY29ycmVjdCBpbmRlZWQsIGJ1dCB3aGF0IGlzIHRoZSBt b3RpdmF0aW9uIGZvciB0aGUgY2hhbmdlLgoKSWYgeW91IG5ldmVyIGV4cGVjdCB0aGlzIHRvIGJl IGluIHNoYXJlZCBlbnZpcm9ubWVudCB3aHkgdG8gZG8gdGhpcz8KU29ycnkgYnV0ICJpdCB3b3Jr cyIgaXMgbm90IGEgZ29vZCBlbm91Z2ggcmVhc29uIGZvciB0aGlzIGNoYW5nZSwgdG8gZW5hYmxl CnVzZWNhc2VzIHdoZXJlIHRoZSBsaW5lIGlzIHNoYXJlZCBpcyBhIGdvb2QgcmVhc29uIDopCg== From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757533AbeD0HDu (ORCPT ); Fri, 27 Apr 2018 03:03:50 -0400 Received: from mga01.intel.com ([192.55.52.88]:55504 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757373AbeD0HDs (ORCPT ); Fri, 27 Apr 2018 03:03:48 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,334,1520924400"; d="scan'208";a="223819743" Date: Fri, 27 Apr 2018 12:38:30 +0530 From: Vinod Koul To: Lars-Peter Clausen Cc: Moritz Fischer , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, dan.j.williams@intel.com Subject: Re: [PATCH v2] dmaengine: axi-dmac: Request IRQ with IRQF_SHARED Message-ID: <20180427070830.GC6014@localhost> References: <20180426174000.12008-1-mdf@kernel.org> <20180427051115.GX6014@localhost> <748ffc14-de12-c11e-eb12-65c599fe5f4e@metafoo.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <748ffc14-de12-c11e-eb12-65c599fe5f4e@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 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 :) -- ~Vinod