linux-kernel - Re: [PATCH v3 20/24] pmdomain: core: Default to use of_genpd_sync

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Message-ID: <CAPDyKFoPOejFT+=OBoLTBXj5GYuHFwwnY9qGROTynrtHT=mCAw@mail.gmail.com>
Date: Wed, 24 Sep 2025 17:53:11 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Jon Hunter <jonathanh@...dia.com>
Cc: Saravana Kannan <saravanak@...gle.com>, Stephen Boyd <sboyd@...nel.org>, linux-pm@...r.kernel.org, 
	"Rafael J . Wysocki" <rafael@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
	Michael Grzeschik <m.grzeschik@...gutronix.de>, Bjorn Andersson <andersson@...nel.org>, 
	Abel Vesa <abel.vesa@...aro.org>, Peng Fan <peng.fan@....nxp.com>, 
	Tomi Valkeinen <tomi.valkeinen@...asonboard.com>, Johan Hovold <johan@...nel.org>, 
	Maulik Shah <maulik.shah@....qualcomm.com>, Michal Simek <michal.simek@....com>, 
	Konrad Dybcio <konradybcio@...nel.org>, Thierry Reding <thierry.reding@...il.com>, 
	Hiago De Franco <hiago.franco@...adex.com>, Geert Uytterhoeven <geert@...ux-m68k.org>, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH v3 20/24] pmdomain: core: Default to use
 of_genpd_sync_state() for genpd providers

On Wed, 24 Sept 2025 at 13:41, Jon Hunter <jonathanh@...dia.com> wrote:
>
> Hi Ulf,
>
> On 03/09/2025 13:33, Jon Hunter wrote:
>
> ...
>
> >>> Following this change I am seeing the following warning on our Tegra194
> >>> devices ...
> >>>
> >>>    WARNING KERN tegra-bpmp bpmp: sync_state() pending due to
> >>> 17000000.gpu
> >>>    WARNING KERN tegra-bpmp bpmp: sync_state() pending due to 3960000.cec
> >>>    WARNING KERN tegra-bpmp bpmp: sync_state() pending due to
> >>> 15380000.nvjpg
> >>>    WARNING KERN tegra-bpmp bpmp: sync_state() pending due to
> >>> 154c0000.nvenc
> >>>    WARNING KERN tegra-bpmp bpmp: sync_state() pending due to
> >>> 15a80000.nvenc
> >>>
> >>> Per your change [0], the 'GENPD_FLAG_NO_SYNC_STATE' is set for Tegra
> >>> and so should Tegra be using of_genpd_sync_state() by default?
> >>
> >> This is a different power-domain provider (bpmp) in
> >> drivers/firmware/tegra/bpmp.c and
> >> drivers/pmdomain/tegra/powergate-bpmp.c.
> >>
> >> For the bpmp we don't need GENPD_FLAG_NO_SYNC_STATE, as the
> >> power-domain provider is described along with the
> >> "nvidia,tegra186-bpmp" compatible string. In the other case
> >> (drivers/soc/tegra/pmc.c) the "core-domain" and "powergates" are
> >> described through child-nodes, while ->sync_state() is managed by the
> >> parent-device-node.
> >>
> >> In the bpmp case there is no ->sync_state() callback assigned, which
> >> means genpd decides to assign a default one.
> >>
> >> The reason for the warnings above is because we are still waiting for
> >> those devices to be probed, hence the ->sync_state() callback is still
> >> waiting to be invoked. Enforcing ->sync_state() callback to be invoked
> >> can be done via user-space if that is needed.
> >>
> >> Did that make sense?
> >
> > Sorry for the delay, I was on vacation. Yes makes sense and drivers for
> > some of the above drivers are not yet upstreamed to mainline and so this
> > would be expected for now.
>
>
> I have been doing more testing and do see a lot of "tegra-bpmp bpmp:
> sync_state() pending due to" on our platforms for basically are driver
> that is built as a module. It seems a bit noisy given that these do
> eventually probe OK. I am wondering if this should be more of a
> dev_info() or dev_dbg() print?

Yes, I agree. We have had similar reports for other platforms too.

I intend to send a patch for this in the next day or so.

Kind regards
Uffe