[Intel-gfx] [PATCH 06/10] drm/i915: don't intel_crt_init if DDI A has 4 lanes

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

DDI A and E have 4 lanes to share, so if DDI A is using 4 lanes,
there's nothing left for DDI E, which means there's no CRT port on the
machine.

The bit we're checking here is programmed at system boot and it cannot
be changed afterwards, so we cannot change the amount of lanes
reserved for each DDI port.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h      | 1 +
 drivers/gpu/drm/i915/intel_display.c | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2d83876..5aba146 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4515,6 +4515,7 @@
 #define  DDI_BUF_EMP_800MV_3_5DB_HSW		(8<<24)   /* Sel8 */
 #define  DDI_BUF_EMP_MASK			(0xf<<24)
 #define  DDI_BUF_IS_IDLE			(1<<7)
+#define  DDI_A_4_LANES				(1<<4)
 #define  DDI_PORT_WIDTH_X1			(0<<1)
 #define  DDI_PORT_WIDTH_X2			(1<<1)
 #define  DDI_PORT_WIDTH_X4			(3<<1)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e4d7079..dd7aafc 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8258,7 +8258,9 @@ static void intel_setup_outputs(struct drm_device *dev)
 		I915_WRITE(PFIT_CONTROL, 0);
 	}
 
-	intel_crt_init(dev);
+	if (!(IS_HASWELL(dev) &&
+	      (I915_READ(DDI_BUF_CTL(PORT_A)) & DDI_A_4_LANES)))
+		intel_crt_init(dev);
 
 	if (IS_HASWELL(dev)) {
 		int found;
-- 
1.7.11.7