[Intel-gfx] [PATCH] drm/i915: Stop sampling rc6 from inside pmu_enable

[Chris Wilson]

Since rc6 is sampling the device registers, we try to acquire the device
wakeref. However, since i915_pmu_enable may be called from hardirq, we
cannot actually wake the device up. So let's not, and hope our gt wake
tracking is accurate.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_pmu.c | 20 --------------------
 1 file changed, 20 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 97bb4aaa5236..b3df73ba1cb0 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -103,11 +103,6 @@ static unsigned int event_bit(struct perf_event *event)
 	return config_bit(event->attr.config);
 }
 
-static bool event_read_needs_wakeref(const struct perf_event *event)
-{
-	return event->attr.config == I915_PMU_RC6_RESIDENCY;
-}
-
 static bool pmu_needs_timer(struct i915_pmu *pmu, bool gpu_active)
 {
 	struct drm_i915_private *i915 = container_of(pmu, typeof(*i915), pmu);
@@ -655,15 +650,10 @@ static void i915_pmu_enable(struct perf_event *event)
 {
 	struct drm_i915_private *i915 =
 		container_of(event->pmu, typeof(*i915), pmu.base);
-	bool need_wakeref = event_read_needs_wakeref(event);
 	struct i915_pmu *pmu = &i915->pmu;
-	intel_wakeref_t wakeref = 0;
 	unsigned long flags;
 	unsigned int bit;
 
-	if (need_wakeref)
-		wakeref = intel_runtime_pm_get(&i915->runtime_pm);
-
 	bit = event_bit(event);
 	if (bit == -1)
 		goto update;
@@ -678,13 +668,6 @@ static void i915_pmu_enable(struct perf_event *event)
 	GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
 	GEM_BUG_ON(pmu->enable_count[bit] == ~0);
 
-	if (pmu->enable_count[bit] == 0 &&
-	    config_mask(I915_PMU_RC6_RESIDENCY) & BIT_ULL(bit)) {
-		pmu->sample[__I915_SAMPLE_RC6_LAST_REPORTED].cur = 0;
-		pmu->sample[__I915_SAMPLE_RC6].cur = __get_rc6(&i915->gt);
-		pmu->sleep_last = ktime_get();
-	}
-
 	pmu->enable |= BIT_ULL(bit);
 	pmu->enable_count[bit]++;
 
@@ -726,9 +709,6 @@ static void i915_pmu_enable(struct perf_event *event)
 	 * an existing non-zero value.
 	 */
 	local64_set(&event->hw.prev_count, __i915_pmu_event_read(event));
-
-	if (wakeref)
-		intel_runtime_pm_put(&i915->runtime_pm, wakeref);
 }
 
 static void i915_pmu_disable(struct perf_event *event)
-- 
2.20.1