From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: Re: [RFC v2 01/11] OPP: Don't overwrite rounded clk rate Date: Mon, 17 Jun 2019 09:20:58 +0530 Message-ID: <20190617035058.veo7uwqjrpa6kykt@vireshk-i7> References: <20190320094918.20234-1-rnayak@codeaurora.org> <20190320094918.20234-2-rnayak@codeaurora.org> <20190611105432.x3nzqiib35t6mvyg@vireshk-i7> <20190612082506.m735bsk7bjijf2yg@vireshk-i7> <20190613095419.lfjeko7nmxtix2n4@vireshk-i7> <20190614052732.4w6vvwwich2h4cgu@vireshk-i7> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190614052732.4w6vvwwich2h4cgu@vireshk-i7> Sender: linux-kernel-owner@vger.kernel.org To: swboyd@chromium.org, Rajendra Nayak , vincent.guittot@linaro.org, mturquette@baylibre.com Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-serial@vger.kernel.org, linux-spi@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-scsi@vger.kernel.org, ulf.hansson@linaro.org, dianders@chromium.org, rafael@kernel.org List-Id: linux-serial@vger.kernel.org On 14-06-19, 10:57, Viresh Kumar wrote: > Hmm, so this patch won't break anything and I am inclined to apply it again :) > > Does anyone see any other issues with it, which I might be missing ? I have updated the commit log a bit more to clarify on things, please let me know if it looks okay. opp: Don't overwrite rounded clk rate The OPP table normally contains 'fmax' values corresponding to the voltage or performance levels of each OPP, but we don't necessarily want all the devices to run at fmax all the time. Running at fmax makes sense for devices like CPU/GPU, which have a finite amount of work to do and since a specific amount of energy is consumed at an OPP, its better to run at the highest possible frequency for that voltage value. On the other hand, we have IO devices which need to run at specific frequencies only for their proper functioning, instead of maximum possible frequency. The OPP core currently roundup to the next possible OPP for a frequency and select the fmax value. To support the IO devices by the OPP core, lets do the roundup to fetch the voltage or performance state values, but not use the OPP frequency value. Rather use the value returned by clk_round_rate(). The current user, cpufreq, of dev_pm_opp_set_rate() already does the rounding to the next OPP before calling this routine and it won't have any side affects because of this change. Signed-off-by: Stephen Boyd Signed-off-by: Rajendra Nayak [ Viresh: Massaged changelog and use temp_opp variable instead ] Signed-off-by: Viresh Kumar -- viresh