[Intel-gfx] [PATCH v3] drm/i915/selftest/gsc: Ensure GSC Proxy init completes before selftests

[Teres Alexis, Alan Previn]

On Tue, 2023-07-11 at 11:49 -0700, Ceraolo Spurio, Daniele wrote:
> <snip>
> > > > @@ -134,6 +193,8 @@ static int __run_selftests(const char *name,
> > > >    {
> > > >    	int err = 0;
> > > >    
> > > > +	__wait_on_all_system_dependencies(data);
> > > Why does this need to be top level selftests and not just a wait for
> > > intel_gsc_uc_fw_proxy_init_done in the tests where it is relevant, via
> > > some helper or something?
> > Alan: it was an offline decision because we didn't want to repeat
> > the same check for all permutations of selftests' subtests (i.e. considering
> > module params can dictate to skip some subtests but execute others).
> > 
> > Anyways, let me get back to you on how how many selftests' subtests actually excercise the
> > need for proxy-init to complete - if its just 1-to-2 subtest I'll move the remove the code
> > from here and move them into the individual subtests.
> 
> I don't think it is going to be easy to figure out which selftest are 
> impacted. All selftests looping on all engines of course, but also tests 
> triggering GT resets and/or messing with the system in other ways. Any 
> new tests added will also need to be evaluated.
> 
> IMO there is minimal impact of having this check on every test. When 
> running selftests we load i915 after the rest of the system has already 
> fully booted, so there are no delays in getting the mei component up and 
> therefore proxy init is sometimes completed even before the selftest 
> code starts; when we do have to wait, it's usually for a very short 
> time, because the expected total execution time for the GSC worker when 
> not having to wait for the mei component to load is ~750ms (~200ms for 
> GSC load + 20ms for HuC auth + ~500ms for proxy init). Having a few 
> seconds added to the total selftests runtime is IMO a better option that 
> having to maintain a list of impacted tests.
> 
> Daniele
> 

Thanks Daniele - I completely forgot about reset or other system disruptive tests.
For now I'll re-rev to address Tvrtko's other comments but will keep the waiter
as 'once-top-down' for now and wait for Tvrtko's thoughts on that next rev.
...alan