[Intel-gfx] [PATCH v2 69/71] drm/i915/chv: Force PHY clock buffers off after PLL disable

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Now that we forced the clock buffers on in .pre_pll_enable() we
should probably undo the damage after we've turned the PLL off.

We do the clock buffer force enable in the .pre_pll_enable() hook
as we need to know which port is going to be used, but in the disable
case we don't need the port since we just disable the clock buffers
to both channels. So we can do this in chv_disable_pll() instead
of having to add any kind of .post_pll_disable() hook.

v2: Improve the commit message

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3215169..376f6c3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1699,6 +1699,17 @@ static void chv_disable_pll(struct drm_i915_private *dev_priv, enum pipe pipe)
 	val &= ~DPIO_DCLKP_EN;
 	vlv_dpio_write(dev_priv, pipe, CHV_CMN_DW14(port), val);
 
+	/* disable left/right clock distribution */
+	if (pipe != PIPE_B) {
+		val = vlv_dpio_read(dev_priv, pipe, _CHV_CMN_DW5_CH0);
+		val &= ~(CHV_BUFLEFTENA1_MASK | CHV_BUFRIGHTENA1_MASK);
+		vlv_dpio_write(dev_priv, pipe, _CHV_CMN_DW5_CH0, val);
+	} else {
+		val = vlv_dpio_read(dev_priv, pipe, _CHV_CMN_DW1_CH1);
+		val &= ~(CHV_BUFLEFTENA2_MASK | CHV_BUFRIGHTENA2_MASK);
+		vlv_dpio_write(dev_priv, pipe, _CHV_CMN_DW1_CH1, val);
+	}
+
 	mutex_unlock(&dev_priv->dpio_lock);
 }
 
-- 
1.8.5.5