[Intel-gfx] [PATCH] drm/i915/bxt: fix RC6 residency time calculation

[Imre Deak]

The RC6 residency time unit is 833.33ns on BXT according to the
specification, so update the calculation accordingly. Use the same way
as CHV/VLV to divide by the corresponding frequency, as I think this is
the more natural unit for what the HW does internally.

Testcase: igt/pm_rc6_residency
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/i915_sysfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 74086eb..7879255 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -54,6 +54,9 @@ static u32 calc_residency(struct drm_device *dev, const u32 reg)
 
 		if (I915_READ(VLV_COUNTER_CONTROL) & VLV_COUNT_RANGE_HIGH)
 			units <<= 8;
+	} else {
+		units = 1;
+		div = 1200;		/* 833.33ns */
 	}
 
 	raw_time = I915_READ(reg) * units;
-- 
2.1.4