drm/i915: Set the transcoder port to none when disabling DP.

The specs say to do so.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

2 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 77b153093cf1..3297cf1a14ed 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3245,6 +3245,7 @@
 #define  TRANS_DP_PORT_SEL_B    (0<<29)
 #define  TRANS_DP_PORT_SEL_C    (1<<29)
 #define  TRANS_DP_PORT_SEL_D    (2<<29)
+#define  TRANS_DP_PORT_SEL_NONE (3<<29)
 #define  TRANS_DP_PORT_SEL_MASK (3<<29)
 #define  TRANS_DP_AUDIO_ONLY    (1<<26)
 #define  TRANS_DP_ENH_FRAMING   (1<<18)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a4acef6c1474..b5f7acf5a9db 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2818,6 +2818,7 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
                 reg = TRANS_DP_CTL(pipe);
                 temp = I915_READ(reg);
                 temp &= ~(TRANS_DP_OUTPUT_ENABLE | TRANS_DP_PORT_SEL_MASK);
+                temp |= TRANS_DP_PORT_SEL_NONE;
                 I915_WRITE(reg, temp);
 
                 /* disable DPLL_SEL */