From: Ville Syrjälä <ville.syrj...@linux.intel.com>
The comment about GMBUSFREQ is confused. The spec actually explains
the 4MHz thing perfectly by noting that the 4MHz divider values is
actually just bits [9:2] not [9:0], hence the divide by 1000 correct.
Replace the confused note with a quote from the spec, and eliminate
the duplicated comment that snuck in.
Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c
b/drivers/gpu/drm/i915/intel_display.c
index ea55dd331fac..ec9144ded255 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5311,18 +5311,13 @@ static void intel_update_cdclk(struct drm_device *dev)
dev_priv->cdclk_freq);
/*
- * Program the gmbus_freq based on the cdclk frequency.
- * BSpec erroneously claims we should aim for 4MHz, but
- * in fact 1MHz is the correct frequency.
+ * 9:0 CMBUS [sic] CDCLK frequency (cdfreq):
+ * Programmng [sic] note: bit[9:2] should be programmed to the number
+ * of cdclk that generates 4MHz reference clock freq which is used to
+ * generate GMBus clock. This will vary with the cdclk freq.
*/
- if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev)) {
- /*
- * Program the gmbus_freq based on the cdclk frequency.
- * BSpec erroneously claims we should aim for 4MHz, but
- * in fact 1MHz is the correct frequency.
- */
+ if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
I915_WRITE(GMBUSFREQ_VLV, DIV_ROUND_UP(dev_priv->cdclk_freq,
1000));
- }
if (dev_priv->max_cdclk_freq == 0)
intel_update_max_cdclk(dev);
--
2.7.4
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