1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index e0843bb99169..58a3755544b2 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -2128,6 +2128,8 @@ static void intel_ddi_clk_select(struct intel_encoder *encoder,
         if (WARN_ON(!pll))
                 return;
 
+         mutex_lock(&dev_priv->dpll_lock);
+
         if (IS_CANNONLAKE(dev_priv)) {
                 /* Configure DPCLKA_CFGCR0 to map the DPLL to the DDI. */
                 val = I915_READ(DPCLKA_CFGCR0);
@@ -2157,6 +2159,8 @@ static void intel_ddi_clk_select(struct intel_encoder *encoder,
         } else if (INTEL_INFO(dev_priv)->gen < 9) {
                 I915_WRITE(PORT_CLK_SEL(port), hsw_pll_to_ddi_pll_sel(pll));
         }
+
+        mutex_unlock(&dev_priv->dpll_lock);
 }
 
 static void intel_ddi_clk_disable(struct intel_encoder *encoder)