[Intel-gfx] [PATCH v4] drm/i915: rc6 in sysfs

[Chris Wilson]

On Wed, 11 Apr 2012 09:14:43 +0100, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> I'm down to just bikeshedding over useless lines of code which do not
> even add visual clarity...
> 
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

Oops, need to learn to spot 64-bit divides which become an issue on
32-bit builds.

diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
index 2319f06..f1b5108 100644
--- a/drivers/gpu/drm/i915/i915_sysfs.c
+++ b/drivers/gpu/drm/i915/i915_sysfs.c
@@ -35,14 +35,12 @@ static u32 calc_residency(struct drm_device *dev, const u32 reg)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u64 raw_time; /* 32b value may overflow during fixed point math */
-	u32 residency;
 
 	if (!intel_enable_rc6(dev))
 		return 0;
 
-	raw_time = I915_READ(reg) * 128ULL;
-	residency = DIV_ROUND_CLOSEST(raw_time, 1000) / 100;
-	return residency;
+	raw_time = I915_READ(reg) * 128ULL + 500;
+	return do_div(raw_time, 100000);
 }
 
 static ssize_t
-- 
1.7.9.5


-- 
Chris Wilson, Intel Open Source Technology Centre