[Intel-gfx] [PATCH] drm/i915/gt: Make the slice:unslice ratio request explicit for RPS

[Chris Wilson]

Quoting Mika Kuoppala (2020-04-21 14:56:46)
> Chris Wilson <chris at chris-wilson.co.uk> writes:
> 
> > Quoting Chris Wilson (2020-04-21 14:45:12)
> >> In RPS, we have the option to only specify the unslice [ring] clock
> >> ratio and for the pcu to derive the slice [gpu] clock ratio from its
> >> magic table. We also have the option to tell the pcu to use our
> >> requested gpu clock ratio, and for it to try and throttle the unslice
> >> and slice ratios separately.
> >> 
> >> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> >> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/gt/intel_rps.c | 11 +++++++----
> >>  1 file changed, 7 insertions(+), 4 deletions(-)
> >> 
> >> diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c
> >> index 4dcfae16a7ce..07321e1b22f6 100644
> >> --- a/drivers/gpu/drm/i915/gt/intel_rps.c
> >> +++ b/drivers/gpu/drm/i915/gt/intel_rps.c
> >> @@ -662,14 +662,17 @@ static int gen6_rps_set(struct intel_rps *rps, u8 val)
> >>         struct drm_i915_private *i915 = rps_to_i915(rps);
> >>         u32 swreq;
> >>  
> >> -       if (INTEL_GEN(i915) >= 9)
> >> -               swreq = GEN9_FREQUENCY(val);
> >> -       else if (IS_HASWELL(i915) || IS_BROADWELL(i915))
> >> +       if (INTEL_GEN(i915) >= 9) {
> >> +               swreq = 0x2; /* only throttle slice, not unslice */
> >
> > 0x0 == use implicit slice ratio
> > 0x1 == use explicit slice ratio
> > 0x2 == use separate throttling
> 
> Care to enum/define these and add as parameter to GEN9_FREQUENCY?

It would not be a parameter to GEN9_FREQUENCY as that gets used
elsewhere. You know my opinion on single use magic macros, only useful
for obfuscating code.
-Chris