[Intel-gfx] [PATCH 8/8] drm/i915/get_params: Add HuC status to getparams

[Chris Wilson]

On Mon, Dec 12, 2016 at 03:52:05PM +0100, Arkadiusz Hiler wrote:
> On Mon, Dec 12, 2016 at 02:21:41PM +0000, Chris Wilson wrote:
> > As for userspace simply asking where huc is enabled, we already have
> > that in the ABI via the module parameter, so you need to justify why
> > this is preferred (in addition to the available information).
> 
> Yeah, we do change the values of module parameters. But a lot of them
> are uid 0 only and we have PARAMS for those.
> 
> Do anything userspace use those actually? Do we plan to use them instead
> of the getparams since now on?

I've done both from userspace... I don't really have a preference, once
you have an fd, an ioctl/GETPARAM is trivial. But for quick querying and
reporting of driver state, reading the module parameter is easier. So I
have a tendency to use an ioctl in production code and module parameter
in igt. (And I would say that for one-off validation purposes, i.e. did
hte module actually enable huc?, just check the module parameter. If
userspace is expected to interact and respond to the setting during its
early probe, make it an ioctl so it fits in with the similar code also
being run at that time.)

It is just worth explaining the intended usecase in the cover note, so
that the use can be sanity checked and reflected upon later if need be.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre