Re: [PATCH v3 20/24] pmdomain: core: Default to use of_genpd_sync_state() for genpd providers

[Jon Hunter <jonathanh@nvidia.com>]

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

-- 
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