[Intel-gfx] [PATCH 1/2] drm/i915: don't disable a PCH DPLL that's in use

[Jesse Barnes]

If a PCH pipe PLL is being used by transcoder C, don't disable it.

Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/intel_display.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 9fa342e..bb8ed3d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1206,7 +1206,8 @@ static void intel_disable_pch_pll(struct drm_i915_private *dev_priv,
 				  enum pipe pipe)
 {
 	int reg;
-	u32 val;
+	u32 val, pll_mask = TRANSC_DPLL_ENABLE | TRANSC_DPLLB_SEL,
+		pll_sel = TRANSC_DPLL_ENABLE;
 
 	if (pipe > 1)
 		return;
@@ -1217,6 +1218,15 @@ static void intel_disable_pch_pll(struct drm_i915_private *dev_priv,
 	/* Make sure transcoder isn't still depending on us */
 	assert_transcoder_disabled(dev_priv, pipe);
 
+	if (pipe == 0)
+		pll_sel |= TRANSC_DPLLA_SEL;
+	else if (pipe == 1)
+		pll_sel |= TRANSC_DPLLB_SEL;
+
+
+	if ((I915_READ(PCH_DPLL_SEL) & pll_mask) == pll_sel)
+		return;
+
 	reg = PCH_DPLL(pipe);
 	val = I915_READ(reg);
 	val &= ~DPLL_VCO_ENABLE;
-- 
1.7.4.1