Re: [Intel-gfx] [PATCH v2 0/3] drm/i915/gt: Expose per gt defaults in sysfs

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Fri, 27 May 2022 16:41:28 -0700, Matt Roper wrote:
>
> On Thu, May 26, 2022 at 12:00:42PM -0700, Ashutosh Dixit wrote:
> > Create a gt/gtN/.defaults directory (similar to
> > engine/<engine-name>/.defaults) to expose default parameter values for each
> > gt in sysfs. This allows userspace to restore default parameter values
> > after they may have changed.
>
> Drive-by comment:  since this is a GT-related change, I think we're
> required to Cc: dri-devel as well.

Sure.

> And since this is new ABI, we'd need an open source userspace consumer
> or a very clear explanation why this is an exception to the rule (e.g.,
> if these are meant to be twiddled directly by the user rather than
> accessed by userspace software).

This series is in response to the following oneAPI requirement ("setting to
-1 will return the frequency to the factory value"):

https://spec.oneapi.io/level-zero/latest/sysman/api.html?highlight=zesfrequencysetrange#zesfrequencysetrange
https://spec.oneapi.io/level-zero/latest/sysman/api.html?highlight=zesfrequencysetrange#_CPPv416zes_freq_range_t

So maybe an open-source oneAPI user mode driver will be acceptable
userspace? So yes not merely to be twiddled just by the user.

Thanks.
--
Ashutosh