From: Viresh Kumar <viresh.kumar@linaro.org>
To: Rex-BC Chen <rex-bc.chen@mediatek.com>
Cc: rafael@kernel.org, robh+dt@kernel.org, krzk+dt@kernel.org,
matthias.bgg@gmail.com, jia-wei.chang@mediatek.com,
roger.lu@mediatek.com, hsinyi@google.com, khilman@baylibre.com,
angelogioacchino.delregno@collabora.com,
linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org,
Project_Global_Chrome_Upstream_Group@mediatek.com
Subject: Re: [PATCH V4 07/14] cpufreq: mediatek: Add .get function
Date: Mon, 25 Apr 2022 15:30:58 +0530 [thread overview]
Message-ID: <20220425100058.4kbvmpi63ygni6k5@vireshk-i7> (raw)
In-Reply-To: <64c690e8edf493ec0a4a14e0fdaad2d8e88e6da7.camel@mediatek.com>
On 25-04-22, 17:34, Rex-BC Chen wrote:
> We found that the pulses of cpu voltage could be observed when
> frequency is fixed (scaling_max_freq == scaling_min_freq) if using
> cpufreq_generic_get as '.get' callback in MT8186.
> cpufreq framework will constantly (~ 1 sec) call 'update' if the policy
Which function gets called here in that case ? I would expect
cpufreq_driver_target() to not make a call to MTK driver in that case, after it
finds that new and old frequency are same (it will check the corresponding freq
from cpufreq table).
> frequency is NOT equal to hardware frequency in
> cpufreq_verify_current_freq.
> The problem is that there might be a tiny difference between the policy
> frequency and the hardware frequency even they are very close.
> e.g. policy frequency is 500,000,000 Hz however, hardware frequency is
> 499,999,726 Hz for MT8186 opp15.
>
> To prevent the voltage pulses, we currently use the software cached
> values as you pointed out.
> I wonder is it possible to add a tolerence for checking difference
> between policy frequency and hardware frequency in cpufreq framework so
> that we can use cpufreq_generic_get as callback without pulse issue.
> Or any suggestion would be appreciated.
--
viresh
next prev parent reply other threads:[~2022-04-25 10:01 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-22 7:52 [PATCH V4 00/14] cpufreq: mediatek: Cleanup and support MT8183 and MT8186 Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 01/14] dt-bindings: cpufreq: mediatek: Add MediaTek CCI property Rex-BC Chen
2022-04-22 8:21 ` AngeloGioacchino Del Regno
2022-04-22 17:26 ` Krzysztof Kozlowski
2022-04-22 17:34 ` Krzysztof Kozlowski
2022-04-25 6:19 ` Rex-BC Chen
2022-04-25 8:55 ` Krzysztof Kozlowski
2022-04-25 10:20 ` Rex-BC Chen
2022-04-25 10:52 ` Krzysztof Kozlowski
2022-04-26 8:26 ` Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 02/14] cpufreq: mediatek: Use device print to show logs Rex-BC Chen
2022-04-25 5:10 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 03/14] cpufreq: mediatek: Replace old_* with pre_* Rex-BC Chen
2022-04-25 5:11 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 04/14] cpufreq: mediatek: Record previous target vproc value Rex-BC Chen
2022-04-22 8:21 ` AngeloGioacchino Del Regno
2022-04-25 5:12 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 06/14] cpufreq: mediatek: Move voltage limits to platform data Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 07/14] cpufreq: mediatek: Add .get function Rex-BC Chen
2022-04-22 8:21 ` AngeloGioacchino Del Regno
2022-04-25 5:35 ` Viresh Kumar
2022-04-25 9:34 ` Rex-BC Chen
2022-04-25 10:00 ` Viresh Kumar [this message]
2022-04-26 11:13 ` Rex-BC Chen
2022-04-27 3:11 ` Viresh Kumar
2022-04-28 11:16 ` Rex-BC Chen
2022-04-28 11:48 ` Viresh Kumar
2022-05-03 11:33 ` Rex-BC Chen
2022-05-04 8:22 ` Viresh Kumar
2022-05-04 11:57 ` Rex-BC Chen
2022-05-04 11:58 ` Viresh Kumar
2022-05-04 12:03 ` Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 08/14] cpufreq: mediatek: Make sram regulator optional Rex-BC Chen
2022-04-25 5:36 ` Viresh Kumar
2022-04-22 7:52 ` [PATCH V4 09/14] cpufreq: mediatek: Refine mtk_cpufreq_voltage_tracking() Rex-BC Chen
2022-04-22 8:20 ` AngeloGioacchino Del Regno
2022-04-22 7:52 ` [PATCH V4 10/14] cpufreq: mediatek: Link CCI device to CPU Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 11/14] cpufreq: mediatek: Add support for MT8186 Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 12/14] arm64: dts: mediatek: Add opp table and clock property for MT8183 cpufreq Rex-BC Chen
2022-04-22 8:20 ` AngeloGioacchino Del Regno
2022-04-22 7:52 ` [PATCH V4 13/14] arm64: dts: mediatek: Add MediaTek CCI node for MT8183 Rex-BC Chen
2022-04-22 7:52 ` [PATCH V4 14/14] arm64: dts: mediatek: Add mediatek,cci property for MT8183 cpufreq Rex-BC Chen
2022-04-22 17:23 ` [PATCH V4 00/14] cpufreq: mediatek: Cleanup and support MT8183 and MT8186 Krzysztof Kozlowski
2022-04-25 6:20 ` Rex-BC Chen
[not found] ` <20220422075239.16437-6-rex-bc.chen@mediatek.com>
2022-04-25 5:20 ` [PATCH V4 05/14] cpufreq: mediatek: Add opp notification support Viresh Kumar
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