drm/i915/chv: Force PHY clock buffers off after PLL disable

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@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 18da083717b9f1439eaf04c7e96c40dee6114ebd..33d7f679e41c59b4e36d7edafe9715dcce87eb6b 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1714,6 +1714,17 @@ 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);
 }