[Intel-gfx] [PATCH 6/6] drm/i915: Use coarse grained residency counter with byt

[Mika Kuoppala]

Set byt rc residency counters high level as chv does by
default. We lose some accuracy on byt but we can do the calculation
without extra hw read on both platforms, as now they behave
identically in this respect.

v2: use ktime

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 9 ++-------
 drivers/gpu/drm/i915/intel_pm.c | 9 +++------
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index f73d8db..7fb35a5 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1100,11 +1100,6 @@ static u32 vlv_wa_c0_ei(struct drm_i915_private *dev_priv, u32 pm_iir)
 	if (prev->ktime) {
 		u64 time, c0;
 		u32 render, media;
-		unsigned int mul;
-
-		mul = 1000 * 100; /* scale to threshold% */
-		if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
-			mul <<= 8;
 
 		time = ktime_us_delta(now.ktime, prev->ktime);
 		time *= dev_priv->czclk_freq;
@@ -1116,8 +1111,8 @@ static u32 vlv_wa_c0_ei(struct drm_i915_private *dev_priv, u32 pm_iir)
 		 */
 		render = now.render_c0 - prev->render_c0;
 		media = now.media_c0 - prev->media_c0;
-		c0 = max(render, media);
-		c0 *= mul;
+		c0 = max_t(u64, render, media) << 8; /* upper part of 40 bit */
+		c0 *= 1000 * 100; /* to usecs and scale to threshold% */
 
 		if (c0 > time * dev_priv->rps.up_threshold)
 			events = GEN6_PM_RP_UP_THRESHOLD;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 19fd11b..41d85ce 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6392,7 +6392,8 @@ static void valleyview_enable_rps(struct drm_i915_private *dev_priv)
 
 	/* allows RC6 residency counter to work */
 	I915_WRITE(VLV_COUNTER_CONTROL,
-		   _MASKED_BIT_ENABLE(VLV_MEDIA_RC0_COUNT_EN |
+		   _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH |
+				      VLV_MEDIA_RC0_COUNT_EN |
 				      VLV_RENDER_RC0_COUNT_EN |
 				      VLV_MEDIA_RC6_COUNT_EN |
 				      VLV_RENDER_RC6_COUNT_EN));
@@ -8361,7 +8362,7 @@ static u64 vlv_residency_raw(struct drm_i915_private *dev_priv,
 	spin_lock_irq(&dev_priv->uncore.lock);
 	saved_ctl = I915_READ_FW(VLV_COUNTER_CONTROL);
 
-	if (!(saved_ctl & VLV_COUNT_RANGE_HIGH))
+	if (WARN_ON(!(saved_ctl & VLV_COUNT_RANGE_HIGH)))
 		I915_WRITE_FW(VLV_COUNTER_CONTROL,
 			      _MASKED_BIT_ENABLE(VLV_COUNT_RANGE_HIGH));
 
@@ -8382,10 +8383,6 @@ static u64 vlv_residency_raw(struct drm_i915_private *dev_priv,
 		upper = I915_READ_FW(reg);
 	} while (upper != tmp);
 
-	if (!(saved_ctl & VLV_COUNT_RANGE_HIGH))
-		I915_WRITE_FW(VLV_COUNTER_CONTROL,
-			      _MASKED_BIT_DISABLE(VLV_COUNT_RANGE_HIGH));
-
 	spin_unlock_irq(&dev_priv->uncore.lock);
 
 	return lower | (u64)upper << 8;
-- 
2.7.4