linux-kernel - Re: [PATCH v2] thermal/drivers/mediatek/lvts_thermal: Make readings valid in filtered mode

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Date:   Fri, 11 Aug 2023 13:01:24 +0200
From:   Alexandre Mergnat <amergnat@...libre.com>
To:     Nícolas F. R. A. Prado 
        <nfraprado@...labora.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     kernel@...labora.com,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Chen-Yu Tsai <wenst@...omium.org>,
        Bernhard Rosenkränzer <bero@...libre.com>,
        Amit Kucheria <amitk@...nel.org>,
        Balsam CHIHI <bchihi@...libre.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Yangtao Li <frank.li@...o.com>,
        Zhang Rui <rui.zhang@...el.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v2] thermal/drivers/mediatek/lvts_thermal: Make readings
 valid in filtered mode

Reviewed-by: Alexandre Mergnat <amergnat@...libre.com>

On 13/07/2023 17:42, Nícolas F. R. A. Prado wrote:
> Currently, when a controller is configured to use filtered mode, thermal
> readings are valid only about 30% of the time.
> 
> Upon testing, it was noticed that lowering any of the interval settings
> resulted in an improved rate of valid data. The same was observed when
> decreasing the number of samples for each sensor (which also results in
> quicker measurements).
> 
> Retrying the read with a timeout longer than the time it takes to
> resample (about 344us with these settings and 4 sensors) also improves
> the rate.
> 
> Lower all timing settings to the minimum, configure the filtering to
> single sample, and poll the measurement register for at least one period
> to improve the data validity on filtered mode.  With these changes in
> place, out of 100000 reads, a single one failed, ie 99.999% of the data
> was valid.

-- 
Regards,
Alexandre