Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753730AbdC3CAC (ORCPT ); Wed, 29 Mar 2017 22:00:02 -0400 Received: from mail-wr0-f171.google.com ([209.85.128.171]:33061 "EHLO mail-wr0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752457AbdC3B77 (ORCPT ); Wed, 29 Mar 2017 21:59:59 -0400 Date: Thu, 30 Mar 2017 09:59:41 +0800 From: Leo Yan To: Mathieu Poirier Cc: Jonathan Corbet , Rob Herring , Mark Rutland , Wei Xu , Catalin Marinas , Will Deacon , Andy Gross , David Brown , Michael Turquette , Stephen Boyd , Guodong Xu , John Stultz , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-clk@vger.kernel.org, mike.leach@linaro.org, Suzuki.Poulose@arm.com, sudeep.holla@arm.com Subject: Re: [PATCH v5 6/9] coresight: add support for CPU debug module Message-ID: <20170330015941.GD3038@leoy-linaro> References: <1490466197-29163-1-git-send-email-leo.yan@linaro.org> <1490466197-29163-7-git-send-email-leo.yan@linaro.org> <20170328165010.GA21937@linaro.org> <20170329015423.GA5035@leoy-linaro> <20170329165535.GB24889@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170329165535.GB24889@linaro.org> 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 Content-Length: 1376 Lines: 37 On Wed, Mar 29, 2017 at 10:55:35AM -0600, Mathieu Poirier wrote: [...] > > So this is why add "idle_constraint" as a central place to control > > power domain for CPU debug purpose and I also think this is more > > friendly for hardware design, e.g. some platforms can enable partial > > low power states to save power and avoid overheat after using this > > driver. > > > > How about you think for this? > > Like Sudeep pointed out we should concentrate on doing the right thing, > that is work with EDPRSR.PU, EDPRCR.COREPURQ and EDPRCR.CORENPDRQ. Agree, and I think we have aligned for this. > Anything outside of that becomes platform specific and can't be handled in > this driver. Sorry I argue a bit for this just want to make things more clear and if can have better method. Though the issue is platform specific, but the code is to seek common method to handle them. So the driver has no any platform specific code. I read again for Suziki's suggestion: "4) Should document the fact that, on some platforms, the user may have to disable CPUidle explicitly to get the driver working. But let us not make it the default. The user with a not so ideal platform could add "nohlt" and get it working." So I'm not strong to resist and if this is alignment yet, I should document well for this but doesn't handle it in driver (keep driver simple). Thanks, Leo Yan