[Intel-gfx] [PATCH 2/2] drm/i915/pmu: Remove fallback to requested freq for SLPC

[Ashutosh Dixit]

The fallback to requested freq does not work for SLPC because SLPC does not
use 'struct intel_rps'. Also for SLPC requested freq can only be obtained
from a hw register after acquiring forcewake which we don't want to do for
PMU. Therefore remove fallback to requested freq for SLPC. The actual freq
will be 0 when gt is in RC6 which is correct. Also this is rare since PMU
freq sampling happens only when gt is unparked.

Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
---
 drivers/gpu/drm/i915/i915_pmu.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 7ece883a7d95..f697fabed64a 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -393,7 +393,14 @@ frequency_sample(struct intel_gt *gt, unsigned int period_ns)
 		 * frequency. Fortunately, the read should rarely fail!
 		 */
 		val = intel_rps_read_actual_frequency_fw(rps);
-		if (!val)
+
+		/*
+		 * SLPC does not use 'struct intel_rps'. Also for SLPC
+		 * requested freq can only be obtained after acquiring
+		 * forcewake and reading a hw register. For SLPC just
+		 * let val be 0
+		 */
+		if (!val && !intel_uc_uses_guc_slpc(&gt->uc))
 			val = intel_gpu_freq(rps, rps->cur_freq);
 
 		add_sample_mult(&pmu->sample[__I915_SAMPLE_FREQ_ACT],
-- 
2.38.0