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[94.29.32.67]) by smtp.googlemail.com with ESMTPSA id f22sm3334897lfa.41.2019.09.30.11.32.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 30 Sep 2019 11:32:52 -0700 (PDT) Subject: Re: [PATCH v5 00/14] Consolidate and improve NVIDIA Tegra CPUIDLE driver(s) To: Thierry Reding Cc: Jonathan Hunter , Peter De Schrijver , "Rafael J. Wysocki" , Daniel Lezcano , linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190929175952.22690-1-digetx@gmail.com> <20190930082645.GF1518582@ulmo> From: Dmitry Osipenko Message-ID: Date: Mon, 30 Sep 2019 21:32:51 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20190930082645.GF1518582@ulmo> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 30.09.2019 11:26, Thierry Reding пишет: > On Sun, Sep 29, 2019 at 08:59:38PM +0300, Dmitry Osipenko wrote: >> Hello, >> >> This series does the following: >> >> 1. Unifies Tegra20/30/114 drivers into a single driver and moves it out >> into common drivers/cpuidle/ directory. >> >> 2. Enables CPU cluster power-down idling state on Tegra30. >> >> In the end there is a quite nice clean up of the Tegra CPUIDLE drivers >> and of the Tegra's arch code in general. Please review, thanks! > > I generally like this series and it looks really good from a diffstat > point of view. However, removing existing drivers completely and then > incrementally add a new one make this impossible to review. > > If you think about it, it also makes it really difficult to find what > went wrong if at any point in the future we find a regression caused by > the new driver. A bisection will always point at the commit that removes > the old driver because between that and the point where you add the new > driver, CPU idle just doesn't work at all anymore. > > While I understand that it's very convenient to just throw away old code > and rewrite it from scratch, it's also impractical (and a little rude). > It's not how we do things in the kernel. Unless maybe under specific > circumstances. > > Can you please try and make this a little more iterative? At the very > least I'd expect a series where you do all the preliminary work in > preparatory patches and then replace the old driver by the new driver in > a single patch. That way at least there will be an unambiguous commit in > a bisection. > > Ideally, you'd also break up that last conversion patch into smaller > incremental patches to make it easier for people to review. Remember > that your chances to attract reviewers increases if you make the patches > easy to review, which means your patches should be small, logical > changes that (ideally) are obviously correct. Thanks for the detailed explanation, probably this is the same what Jon was asking to do. Now I see what you're are asking for.