From: Thara Gopinath <thara.gopinath@linaro.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: agross@kernel.org, rui.zhang@intel.com, viresh.kumar@linaro.org,
rjw@rjwysocki.net, robh+dt@kernel.org, steev@kali.org,
tdas@codeaurora.org, mka@chromium.org,
linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [Patch v5 2/6] thermal: qcom: Add support for LMh driver
Date: Tue, 31 Aug 2021 10:52:27 -0400 [thread overview]
Message-ID: <299e2a59-ae4e-278d-200d-630f055c1411@linaro.org> (raw)
In-Reply-To: <a216c89d-6cd5-326d-f203-f48caaf2a096@linaro.org>
On 8/23/21 11:57 AM, Daniel Lezcano wrote:
>
> Hi Bjorn,
>
> On 23/08/2021 17:05, Bjorn Andersson wrote:
>> On Sat 21 Aug 02:41 PDT 2021, Daniel Lezcano wrote:
>>
>>>
>>> Hi Thara,
>>>
>>> On 09/08/2021 21:16, Thara Gopinath wrote:
>>>> Driver enabling various pieces of Limits Management Hardware(LMh) for cpu
>>>> cluster0 and cpu cluster1 namely kick starting monitoring of temperature,
>>>> current, battery current violations, enabling reliability algorithm and
>>>> setting up various temperature limits.
>>>>
>>>> The following has been explained in the cover letter. I am including this
>>>> here so that this remains in the commit message as well.
>>>>
>>>> LMh is a hardware infrastructure on some Qualcomm SoCs that can enforce
>>>> temperature and current limits as programmed by software for certain IPs
>>>> like CPU. On many newer LMh is configured by firmware/TZ and no programming
>>>> is needed from the kernel side. But on certain SoCs like sdm845 the
>>>> firmware does not do a complete programming of the h/w. On such soc's
>>>> kernel software has to explicitly set up the temperature limits and turn on
>>>> various monitoring and enforcing algorithms on the hardware.
>>>>
>>>> Tested-by: Steev Klimaszewski <steev@kali.org> # Lenovo Yoga C630
>>>> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
>>>
>>> Is it possible to have an option to disable/enable the LMh driver at
>>> runtime, for instance with a module parameter ?
>>>
>>
>> Are you referring to being able to disable the hardware throttling, or
>> the driver's changes to thermal pressure?
>
> The former.
Hi Daniel,
It is not recommended to turn off LMh once enabled. From h/w point of
view, it can be done for debug purposes but it is not to be implemented
as a feature.
>
>> I'm not aware of any way to disable the hardware. I do remember that
>> there was some experiments done (with a hacked up boot chain) early on
>> and iirc it was concluded that it's not a good idea.
>
> My objective was to test the board with the thermal framework handling
> the mitigation instead of the hardware.
>
> I guess I can set the hardware temperature higher than the thermal zone
> temperature.
Right. Also remember that patch 5 in this series removes the cooling
devices for the cpu thermal zones. So if you are testing this you will
have to add them back.
>
> On which sensor the lmh does refer to ? The cluster one ?
>
> (by the way the thermal zone temperatures per core are lower by 5°C than
> the hardware mitigation ? is it done on purpose ?)
So IIUC, it refers to tsens for individual cpus and collates the input.
But the documentation is not clear on this one. I took the mitigation
temperature from downstream code. Yes I did realize that the thermal
zone trip1 temp is 90 degree where as the LMh mitigation point is 95
degree. My thinking is this is because the h/w mitigation can happen
faster than s/w and hence the 5 degree bump up in temperature.
>
>> Either way, if there is a way and there is a use for it, we can always
>> add such parameter incrementally. So I suggest that we merge this as is.
>
> Yes, that was for my information. It is already merged.
Thank you very much
>
> Thanks
>
> -- Daniel
>
--
Warm Regards
Thara (She/Her/Hers)
next prev parent reply other threads:[~2021-08-31 14:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-09 19:15 [Patch v5 0/6] Introduce LMh driver for Qualcomm SoCs Thara Gopinath
2021-08-09 19:15 ` [Patch v5 1/6] firmware: qcom_scm: Introduce SCM calls to access LMh Thara Gopinath
2021-08-17 13:17 ` Daniel Lezcano
2021-08-17 14:07 ` Bjorn Andersson
2021-08-17 14:08 ` Daniel Lezcano
2021-08-09 19:16 ` [Patch v5 2/6] thermal: qcom: Add support for LMh driver Thara Gopinath
2021-08-21 9:41 ` Daniel Lezcano
2021-08-23 15:05 ` Bjorn Andersson
2021-08-23 15:57 ` Daniel Lezcano
2021-08-31 14:52 ` Thara Gopinath [this message]
2021-08-09 19:16 ` [Patch v5 3/6] cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support Thara Gopinath
2021-08-10 2:47 ` Viresh Kumar
2021-08-11 11:27 ` Thara Gopinath
2021-08-18 3:37 ` Viresh Kumar
2021-08-09 19:16 ` [Patch v5 4/6] arm64: dts: qcom: sdm45: Add support for LMh node Thara Gopinath
2021-08-09 19:16 ` [Patch v5 5/6] arm64: dts: qcom: sdm845: Remove cpufreq cooling devices for CPU thermal zones Thara Gopinath
2021-08-09 19:16 ` [Patch v5 6/6] dt-bindings: thermal: Add dt binding for QCOM LMh Thara Gopinath
2021-08-09 19:16 ` Thara Gopinath
2021-08-17 18:56 ` Rob Herring
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