Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756092AbcJFRiI (ORCPT ); Thu, 6 Oct 2016 13:38:08 -0400 Received: from mx2.suse.de ([195.135.220.15]:48572 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756053AbcJFRiA (ORCPT ); Thu, 6 Oct 2016 13:38:00 -0400 Date: Thu, 6 Oct 2016 19:37:56 +0200 From: "Luis R. Rodriguez" To: Marek Szyprowski Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-samsung-soc@vger.kernel.org, Joerg Roedel , Inki Dae , Kukjin Kim , Krzysztof Kozlowski , Bartlomiej Zolnierkiewicz , "Rafael J. Wysocki" , Mark Brown , "Luis R. Rodriguez" , Greg Kroah-Hartman , Tomeu Vizoso , Lukas Wunner , Kevin Hilman , Tobias Jakobi Subject: Re: [PATCH v4 2/2] iommu/exynos: Add proper runtime pm support Message-ID: <20161006173756.GK3296@wotan.suse.de> References: <1475136751-31340-1-git-send-email-m.szyprowski@samsung.com> <1475136751-31340-3-git-send-email-m.szyprowski@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1475136751-31340-3-git-send-email-m.szyprowski@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1426 Lines: 35 On Thu, Sep 29, 2016 at 10:12:31AM +0200, Marek Szyprowski wrote: > This patch uses recently introduced device links to track the runtime pm > state of the master's device. This way each SYSMMU controller is runtime > activated when its master's device is active instead of? BTW what is the master device of a SYSMMU? I have no clue about these IOMMU devices here. > and can save/restore its state instead of being enabled all the time. I take it this means currently even if the master device is disabled (whatever that is) all SYSMMU controllers are kept enabled, is that right? The issue here is this wastes power? Or what is the issue? > This way SYSMMU controllers no > longer prevents respective power domains to be turned off when master's > device is not used. So when the master device is idle we want to also remove power from the controllers ? How much power does this save on a typical device in the market BTW ? > Signed-off-by: Marek Szyprowski > --- > drivers/iommu/exynos-iommu.c | 225 ++++++++++++++++++------------------------- > 1 file changed, 94 insertions(+), 131 deletions(-) I'm reviewing the device link patches now but since this is a demo of use of that I'll note the changes here are pretty large and it makes it terribly difficult for review. Is there any way this patch can be split up in to logical atomic pieces that only do one task upon change ? Luis