From: Rajendra Nayak <rnayak@codeaurora.org>
To: Viresh Kumar <viresh.kumar@linaro.org>,
swboyd@chromium.org, 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
Subject: Re: [RFC v2 01/11] OPP: Don't overwrite rounded clk rate
Date: Mon, 17 Jun 2019 09:37:02 +0530 [thread overview]
Message-ID: <a912c8b2-080d-7ab7-670b-b687ec3a2c92@codeaurora.org> (raw)
In-Reply-To: <20190617035058.veo7uwqjrpa6kykt@vireshk-i7>
On 6/17/2019 9:20 AM, Viresh Kumar wrote:
> 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.
Looks good to me. Should this also be documented someplace that dev_pm_opp_set_rate()
would not be able to distinguish between its users trying to scale CPU/GPU's vs IO
devices, so its the callers responsibility to round it accordingly before calling the
API?
>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
> [ Viresh: Massaged changelog and use temp_opp variable instead ]
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>
>
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
next prev parent reply other threads:[~2019-06-17 4:07 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 9:49 [RFC v2 00/11] DVFS in the OPP core Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 01/11] OPP: Don't overwrite rounded clk rate Rajendra Nayak
2019-06-11 10:54 ` Viresh Kumar
2019-06-12 7:42 ` Rajendra Nayak
2019-06-12 8:25 ` Viresh Kumar
2019-06-13 9:54 ` Viresh Kumar
2019-06-14 5:27 ` Viresh Kumar
2019-06-17 3:50 ` Viresh Kumar
2019-06-17 4:07 ` Rajendra Nayak [this message]
2019-06-17 4:17 ` Viresh Kumar
2019-06-17 4:25 ` Rajendra Nayak
2019-06-14 5:54 ` Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 02/11] OPP: Make dev_pm_opp_set_rate() with freq=0 as valid Rajendra Nayak
2019-06-14 6:32 ` Viresh Kumar
2019-06-17 4:04 ` Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 03/11] tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state Rajendra Nayak
2020-08-11 23:11 ` John Stultz
2020-08-12 1:33 ` John Stultz
2020-08-12 5:48 ` Rajendra Nayak
2020-08-12 7:35 ` Amit Pundir
2020-08-12 7:39 ` Rajendra Nayak
2020-08-12 9:26 ` Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 04/11] spi: spi-geni-qcom: " Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 05/11] arm64: dts: sdm845: Add OPP table for all qup devices Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 06/11] scsi: ufs: Add support to manage multiple power domains in ufshcd-pltfrm Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 07/11] scsi: ufs: Add support for specifying OPP tables in DT Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 08/11] arm64: dts: sdm845: Add ufs opps and power-domains Rajendra Nayak
2019-05-14 7:53 ` Ulf Hansson
2019-03-20 9:49 ` [RFC v2 09/11] drm/msm/dpu: Use OPP API to set clk/perf state Rajendra Nayak
2019-04-10 3:49 ` Viresh Kumar
2019-04-10 3:49 ` Viresh Kumar
2019-03-20 9:49 ` [RFC v2 10/11] drm/msm: dsi: " Rajendra Nayak
2019-03-20 9:49 ` [RFC v2 11/11] arm64: dts: sdm845: Add DSI and MDP OPP tables and power-domains Rajendra Nayak
2019-04-10 3:51 ` [RFC v2 00/11] DVFS in the OPP core Viresh Kumar
2019-04-10 3:51 ` Viresh Kumar
2019-05-21 6:22 ` Viresh Kumar
2019-05-24 6:03 ` Rajendra Nayak
2019-06-17 4:26 ` Viresh Kumar
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