Re: [PATCH 3/3] drm/debugfs: remove dev->debugfs_list and debugfs_mutex

[Jani Nikula <jani.nikula@linux.intel.com>]

On Fri, 17 Feb 2023, Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com> wrote:
> On Thu, Feb 16, 2023 at 07:06:46PM +0200, Jani Nikula wrote:
>> >
>> > But should not this the driver responsibility, call drm_debugfs_add_file()
>> > whenever you are ready to handle operations on added file ?
>> 
>> In theory, yes, but in practice it's pretty hard for a non-trivial
>> driver to maintain that all the conditions are met.
>
> Hmmm... 
>
>> In i915 we call debugfs register all over the place only after we've
>> called drm_dev_register(), because it's the only sane way. But it means
>> we need the init and register separated everywhere, instead of init
>> adding files to a list to be registered later.
>
> Isn't this done this way in i915 only because it was not possible
> (and still isn't) to call drm_debugfs_create_file() before registration ?
>
> I think it's should be ok by i915 subsystem to create it's debugfs
> files and allow to access to them just after that subsystem init.
>
> Or there are some complex dependencies between i915 subsystems,
> that reading registers from one subsystem will corrupt some
> other subsystem that did non finish initialization yet?

That's the point. It's really hard to figure it all out. Why bother?

BR,
Jani.


>
> Regards
> Stanislaw

-- 
Jani Nikula, Intel Open Source Graphics Center