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

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@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@chris-wilson.co.uk>
>> Cc: Mika Kuoppala <mika.kuoppala@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?

Also if there is any bspec link, add a reference.

Thanks,
-Mika

>
> Not sure if 0x2 actually was implemented in the end.
> -Chris
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