[PATCH 7/9] drm/i915: Use CK505 as non-SSC source where available

From: Keith Packard
Date: Tue Sep 27 2011 - 02:12:31 EST


This eliminates VGA shimmer on some Ironlake machines which have a
CK505 clock source.

Signed-off-by: Keith Packard <keithp@xxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_display.c | 12 +++++++++---
1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f999935..66cd351 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5137,8 +5137,10 @@ static void ironlake_update_pch_refclk(struct drm_device *dev)
break;
}
}
- DRM_DEBUG_KMS("has_panel %d has_lvds %d has_pch_edp %d has_cpu_edp %d\n",
- has_panel, has_lvds, has_pch_edp, has_cpu_edp);
+
+ DRM_DEBUG_KMS("has_panel %d has_lvds %d has_pch_edp %d has_cpu_edp %d has_ck505 %d\n",
+ has_panel, has_lvds, has_pch_edp, has_cpu_edp,
+ dev_priv->display_clock_mode);

/* Ironlake: try to setup display ref clock before DPLL
* enabling. This is only under driver's control after
@@ -5148,7 +5150,11 @@ static void ironlake_update_pch_refclk(struct drm_device *dev)
temp = I915_READ(PCH_DREF_CONTROL);
/* Always enable nonspread source */
temp &= ~DREF_NONSPREAD_SOURCE_MASK;
- temp |= DREF_NONSPREAD_SOURCE_ENABLE;
+
+ if (dev_priv->display_clock_mode)
+ temp |= DREF_NONSPREAD_CK505_ENABLE;
+ else
+ temp |= DREF_NONSPREAD_SOURCE_ENABLE;

if (has_panel) {
temp &= ~DREF_SSC_SOURCE_MASK;
--
1.7.6.3

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