Message-ID: <CABjd4YysYZ5o17-nhRjyKqAw2sWi=GR1Q_OSHzAFOHLF5vh9GQ@mail.gmail.com>
Date: Tue, 28 May 2024 20:01:39 +0400
From: Alexey Charkov <alchark@...il.com>
To: Heiko Stuebner <heiko@...ech.de>
Cc: Dragan Simic <dsimic@...jaro.org>, Quentin Schulz <quentin.schulz@...rry.de>, 
	Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Daniel Lezcano <daniel.lezcano@...aro.org>, Viresh Kumar <viresh.kumar@...aro.org>, 
	Chen-Yu Tsai <wens@...nel.org>, Diederik de Haas <didi.debian@...ow.org>, devicetree@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 0/6] RK3588 and Rock 5B dts additions: thermal, OPP and fan

[sorry if you get this twice: I messed up and sent the previous one in
HTML instead of plain text - resending now]

On Tue, May 28, 2024 at 7:16 PM Heiko Stuebner <heiko@...ech.de> wrote:
>
> Am Dienstag, 28. Mai 2024, 17:01:48 CEST schrieb Dragan Simic:
> > On 2024-05-28 16:34, Heiko Stuebner wrote:
> > > Am Dienstag, 28. Mai 2024, 16:05:04 CEST schrieb Dragan Simic:
> > >> On 2024-05-28 11:49, Alexey Charkov wrote:
> > >> > On Mon, May 6, 2024 at 1:37 PM Alexey Charkov <alchark@...il.com>
> > >> > wrote:
> > >> >>
> > >> >> This enables thermal monitoring and CPU DVFS on RK3588(s), as well as
> > >> >> active cooling on Radxa Rock 5B via the provided PWM fan.
> > >> >>
> > >> >> Some RK3588 boards use separate regulators to supply CPUs and their
> > >> >> respective memory interfaces, so this is handled by coupling those
> > >> >> regulators in affected boards' device trees to ensure that their
> > >> >> voltage is adjusted in step.
> > >> >>
> > >> >> This also enables the built-in thermal sensor (TSADC) for all boards
> > >> >> that don't currently have it enabled, using the default CRU based
> > >> >> emergency thermal reset. This default configuration only uses on-SoC
> > >> >> devices and doesn't rely on any external wiring, thus it should work
> > >> >> for all devices (tested only on Rock 5B though).
> > >> >>
> > >> >> The boards that have TSADC_SHUT signal wired to the PMIC reset line
> > >> >> can choose to override the default reset logic in favour of GPIO
> > >> >> driven (PMIC assisted) reset, but in my testing it didn't work on
> > >> >> Radxa Rock 5B - maybe I'm reading the schematic wrong and it doesn't
> > >> >> support PMIC assisted reset after all.
> > >> >>
> > >> >> Fan control on Rock 5B has been split into two intervals: let it spin
> > >> >> at the minimum cooling state between 55C and 65C, and then accelerate
> > >> >> if the system crosses the 65C mark - thanks to Dragan for suggesting.
> > >> >> This lets some cooling setups with beefier heatsinks and/or larger
> > >> >> fan fins to stay in the quietest non-zero fan state while still
> > >> >> gaining potential benefits from the airflow it generates, and
> > >> >> possibly avoiding noisy speeds altogether for some workloads.
> > >> >>
> > >> >> OPPs help actually scale CPU frequencies up and down for both cooling
> > >> >> and performance - tested on Rock 5B under varied loads. I've dropped
> > >> >> those OPPs that cause frequency reductions without accompanying
> > >> >> decrease
> > >> >> in CPU voltage, as they don't seem to be adding much benefit in day to
> > >> >> day use, while the kernel log gets a number of "OPP is inefficient"
> > >> >> lines.
> > >> >>
> > >> >> Note that this submission doesn't touch the SRAM read margin updates
> > >> >> or
> > >> >> the OPP calibration based on silicon quality which the downstream
> > >> >> driver
> > >> >> does and which were mentioned in [1]. It works as it is (also
> > >> >> confirmed by
> > >> >> Sebastian in his follow-up message [2]), and it is stable in my
> > >> >> testing on
> > >> >> Rock 5B, so it sounds better to merge a simple version first and then
> > >> >> extend when/if required.
> > >> >>
> > >> >> [1]
> > >> >> https://lore.kernel.org/linux-rockchip/CABjd4YzTL=5S7cS8ACNAYVa730WA3iGd5L_wP1Vn9=f83RCORA@mail.gmail.com/
> > >> >> [2]
> > >> >> https://lore.kernel.org/linux-rockchip/pkyne4g2cln27dcdu3jm7bqdqpmd2kwkbguiolmozntjuiajrb@gvq4nupzna4o/
> > >> >>
> > >> >> Signed-off-by: Alexey Charkov <alchark@...il.com>
> > >> >> ---
> > >> >
> > >> > Hi Heiko,
> > >> >
> > >> > Do you think this can be merged for 6.11? Looks like there hasn't been
> > >> > any new feedback in a while, and it would be good to have frequency
> > >> > scaling in place for RK3588.
> > >> >
> > >> > Please let me know if you have any reservations or if we need any
> > >> > broader discussion.
> > >
> > > not really reservations, more like there was still discussion going on
> > > around the OPPs. Meanwhile we had more discussions regarding the whole
> > > speed binning Rockchip seems to do for rk3588 variants.
> > >
> > > And waiting for the testing Dragan wanted to do ;-) .
> >
> > I'm sorry for the delays.
>
> Was definitly _not_ meant as blame ;-) .
>
> The series has just too many discussions threads to unravel on half
> an afternoon.

FWIW, I think the latest exchange we had with Quentin regarding the
OPPs concluded in “false alarm”, given that this version of the series
only introduces a subset of them which should apply to all RK3588(s)

Performance binning here is more geared towards how low the voltages
can go for a given frequency, and right now we’re only introducing the
highest-voltage setting for each OPP. Thus the binning and/or
intermediate frequencies should be possible to introduce at a later
stage in a backwards compatible way (if deemed relevant).

> > > So this should definitly make it into 6.11 though, as there is still
> > > a lot of time.
> > >
> > >> As I promised earlier, I was going to test this patch series in
> > >> detail.
> > >> Alas, I haven't managed to do that yet, :/ due to many reasons, but
> > >> I still remain firmly committed to doing that.
> > >>
> > >> Is -rc4 the cutoff for 6.11?  If so, there's still time and I'll do my
> > >> best to test and review these patches as soon as possible.
> > >
> > > As early as possible, the hard cutoff would be -rc6 though.
> > > I guess I'll just start picking the easy patches from the series.
> >
> > I'll do my best to have the patches tested and reviewed in detail ASAP.
> > As a suggestion, perhaps it would be better to take the series as a
> > whole,
> > so we don't bring partial merging into the mix.
>
> Patches need to work individually anyway (in correct order of course),
> so like starting at the top with the general thermal stuff should not
> create issues ;-)

Indeed, those are self-contained and can be merged independently of
the OPPs. Having OPPs without thermal is more risky though, but that
doesn’t sound like what we’re after here :)

Best regards,
Alexey

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