[Intel-gfx] [PATCH 1/2] drm/i915/params: add i915 parameters to debugfs

[Jani Nikula]

On Wed, 15 Jan 2020, Jani Nikula <jani.nikula at intel.com> wrote:
> On Wed, 15 Jan 2020, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>> Quoting Jani Nikula (2019-12-05 15:43:40)
>>> Add a debugfs subdirectory i915_params with all the i915 module
>>> parameters. This is a first step, with lots of boilerplate, and not much
>>> benefit yet.
>>
>> Right, creates a mirror [more or less] of /sys/module/i915/parameters. I
>> probably would have used parameters/ rather than i915_params/, but that
>> is immaterial.
>
> I guess I used i915_ because it's sort of a shared namespace with drm
> core, which in itself is, IMO, a historical mistake. Perhaps there
> should've been a driver/ debugfs directory for driver specific debug
> files.
>
> What if someone wanted to add a drm core level parameters/ file or
> directory? Would be kind of embarrassing to say, don't do that, i915
> already uses it...
>
>>> 
>>> This will result in a new device specific debugfs directory at
>>> /sys/kernel/debug/dri/<N>/i915_params duplicating the module specific
>>> sysfs directory at /sys/module/i915/parameters/. Going forward, all
>>> users of the parameters should use the debugfs, with the module
>>> parameters being phased out.
>>> 
>>> Add debugfs permissions to I915_PARAMS_FOR_EACH(). This duplicates the
>>> mode with module parameter sysfs, but the goal is to make the module
>>> parameters read-only initial values for device specific parameters.
>>> 
>>> 0 mode will bypass debugfs creation. Use it for verbose_state_checks
>>> which will need special attention in follow-up work.
>>
>> The patch does what you say, hopefully a local entropy maxima.
>> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
>
> Many thanks,
> Jani.

And pushed both to dinq, thanks again for the review.

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center