[Intel-gfx] [PATCH] drm/i915: fix WRPLL clock calculation

Jesse Barnes jbarnes at virtuousgeek.org
Wed Jan 22 21:58:04 CET 2014


Forgot to convert to using the refclk variable when I added refclk
readout support, and Paulo noticed the resulting calculation was off due
to the way p & r are stored.

Reported-by: Paulo Zanoni <przanoni at gmail.com>
Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/intel_ddi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index fe2967e..cd65dd0 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -663,7 +663,8 @@ static int intel_ddi_calc_wrpll_link(struct drm_i915_private *dev_priv,
 	p = (wrpll & WRPLL_DIVIDER_POST_MASK) >> WRPLL_DIVIDER_POST_SHIFT;
 	n = (wrpll & WRPLL_DIVIDER_FB_MASK) >> WRPLL_DIVIDER_FB_SHIFT;
 
-	return (LC_FREQ * n) / (p * r);
+	/* Convert to KHz, p & r have a fixed point portion */
+	return (refclk * n * 100) / (p * r);
 }
 
 static void intel_ddi_clock_get(struct intel_encoder *encoder,
-- 
1.8.3.2




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