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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <614f726c-4d6d-463b-a8b3-26d3df590575@nvidia.com>
Date: Wed, 24 Sep 2025 12:40:59 +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

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?

Cheers
Jon

-- 
nvpublic