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

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Message-ID: <9d084f85-1368-4974-bbf8-588140422040@nvidia.com>
Date: Thu, 25 Sep 2025 10:34:00 +0100
From: Jon Hunter <jonathanh@...dia.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
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 24/09/2025 16:53, Ulf Hansson wrote:
> 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.

OK great! Please CC me and I will be happy to test.

Cheers
Jon

-- 
nvpublic