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path: root/drivers/gpu/drm/i915/intel_display.c
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Diffstat (limited to 'drivers/gpu/drm/i915/intel_display.c')
-rw-r--r--drivers/gpu/drm/i915/intel_display.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 123cce1ae470..db4c38700951 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2814,6 +2814,46 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
link_bw, &m_n);
}
+ /* Ironlake: try to setup display ref clock before DPLL
+ * enabling. This is only under driver's control after
+ * PCH B stepping, previous chipset stepping should be
+ * ignoring this setting.
+ */
+ if (IS_IGDNG(dev)) {
+ temp = I915_READ(PCH_DREF_CONTROL);
+ /* Always enable nonspread source */
+ temp &= ~DREF_NONSPREAD_SOURCE_MASK;
+ temp |= DREF_NONSPREAD_SOURCE_ENABLE;
+ I915_WRITE(PCH_DREF_CONTROL, temp);
+ POSTING_READ(PCH_DREF_CONTROL);
+
+ temp &= ~DREF_SSC_SOURCE_MASK;
+ temp |= DREF_SSC_SOURCE_ENABLE;
+ I915_WRITE(PCH_DREF_CONTROL, temp);
+ POSTING_READ(PCH_DREF_CONTROL);
+
+ udelay(200);
+
+ if (is_edp) {
+ if (dev_priv->lvds_use_ssc) {
+ temp |= DREF_SSC1_ENABLE;
+ I915_WRITE(PCH_DREF_CONTROL, temp);
+ POSTING_READ(PCH_DREF_CONTROL);
+
+ udelay(200);
+
+ temp &= ~DREF_CPU_SOURCE_OUTPUT_MASK;
+ temp |= DREF_CPU_SOURCE_OUTPUT_DOWNSPREAD;
+ I915_WRITE(PCH_DREF_CONTROL, temp);
+ POSTING_READ(PCH_DREF_CONTROL);
+ } else {
+ temp |= DREF_CPU_SOURCE_OUTPUT_NONSPREAD;
+ I915_WRITE(PCH_DREF_CONTROL, temp);
+ POSTING_READ(PCH_DREF_CONTROL);
+ }
+ }
+ }
+
if (IS_IGD(dev)) {
fp = (1 << clock.n) << 16 | clock.m1 << 8 | clock.m2;
if (has_reduced_clock)
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