From: Viresh Kumar <viresh.kumar@linaro.org>
To: "Marek Behún" <kabel@kernel.org>
Cc: "Gregory CLEMENT" <gregory.clement@bootlin.com>,
"Ken Ma" <make@marvell.com>, "Victor Gu" <xigu@marvell.com>,
"Robert Marko" <robert.marko@sartura.hr>,
"Pali Rohár" <pali@kernel.org>,
"Tomasz Maciej Nowak" <tmn505@gmail.com>,
"Anders Trier Olesen" <anders.trier.olesen@gmail.com>,
"Philip Soares" <philips@netisense.com>,
linux-pm@vger.kernel.org,
"Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>,
linux-arm-kernel@lists.infradead.org,
"Konstantin Porotchkin" <kostap@marvell.com>,
nnet <nnet@fastmail.fm>, "Nadav Haklai" <nadavh@marvell.com>
Subject: Re: [PATCH v2] cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant
Date: Thu, 1 Jul 2021 07:35:51 +0530 [thread overview]
Message-ID: <20210701020551.svhbjpbdw526cq7a@vireshk-i7> (raw)
In-Reply-To: <20210630225601.6372-1-kabel@kernel.org>
On 01-07-21, 00:56, Marek Behún wrote:
> The 1.2 GHz variant of the Armada 3720 SOC is unstable with DVFS: when
> the SOC boots, the WTMI firmware sets clocks and AVS values that work
> correctly with 1.2 GHz CPU frequency, but random crashes occur once
> cpufreq driver starts scaling.
>
> We do not know currently what is the reason:
> - it may be that the voltage value for L0 for 1.2 GHz variant provided
> by the vendor in the OTP is simply incorrect when scaling is used,
> - it may be that some delay is needed somewhere,
> - it may be something else.
>
> The most sane solution now seems to be to simply forbid the cpufreq
> driver on 1.2 GHz variant.
>
> Signed-off-by: Marek Behún <kabel@kernel.org>
> Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
> ---
> If someone from Marvell could look into this, it would be great since
> basically 1.2 GHz variant cannot scale, which is a feature that was
> claimed to be supported by the SOC.
>
> Ken Ma / Victor Gu, you have worked on commit
> https://github.com/MarvellEmbeddedProcessors/linux-marvell/commit/d6719fdc2b3cac58064f41b531f86993c919aa9a
> in linux-marvell.
> Your patch takes away the 1202 mV constant for 1.2 GHz base CPU
> frequency and instead adds code that computes the voltages from the
> voltage found in L0 AVS register (which is filled in by WTMI firmware).
>
> Do you know why the code does not work correctly for some 1.2 GHz
> boards? Do we need to force the L0 voltage to 1202 mV if it is lower,
> or something?
> ---
> drivers/cpufreq/armada-37xx-cpufreq.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
I am not picking it up for 5.14-rc1 to make sure others get a chance
to provide reviews.
--
viresh
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next prev parent reply other threads:[~2021-07-01 2:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-30 13:59 [PATCH] cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant Marek Behún
2021-06-30 14:02 ` Marek Behún
2021-06-30 15:22 ` Andrew Lunn
2021-06-30 22:56 ` [PATCH v2] " Marek Behún
2021-07-01 2:05 ` Viresh Kumar [this message]
2021-07-02 16:30 ` Pali Rohár
2021-07-08 14:34 ` Pali Rohár
2021-07-15 19:33 ` Pali Rohár
2021-08-08 19:30 ` Pali Rohár
2021-08-09 4:02 ` Viresh Kumar
2022-08-01 12:36 ` Pali Rohár
2022-08-01 14:01 ` [EXT] " Elad Nachman
2022-08-01 14:12 ` Pali Rohár
2022-08-01 14:15 ` Elad Nachman
2022-08-01 17:56 ` Pali Rohár
[not found] ` <BN9PR18MB42518C761E574D862D30CDA7DB9A9@BN9PR18MB4251.namprd18.prod.outlook.com>
2022-08-02 16:42 ` Robert Marko
2022-08-02 16:52 ` Elad Nachman
2022-08-02 16:56 ` Robert Marko
2022-08-02 17:17 ` Pali Rohár
2022-08-17 9:40 ` Robert Marko
2022-08-17 23:10 ` Pali Rohár
2022-08-18 8:14 ` Robert Marko
2022-08-25 21:49 ` Pali Rohár
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