From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luis R. Rodriguez" Subject: Re: [PATCH v4 2/2] iommu/exynos: Add proper runtime pm support Date: Thu, 6 Oct 2016 19:37:56 +0200 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-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1475136751-31340-3-git-send-email-m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Marek Szyprowski Cc: Krzysztof Kozlowski , linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tomeu Vizoso , linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Greg Kroah-Hartman , Bartlomiej Zolnierkiewicz , "Rafael J. Wysocki" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Inki Dae , Kevin Hilman , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Kukjin Kim , Mark Brown , Tobias Jakobi , Lukas Wunner , "Luis R. Rodriguez" List-Id: linux-samsung-soc@vger.kernel.org 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