drm/i915: don't intel_crt_init if DDI A has 4 lanes

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@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 2d838766418b3035bc996e7ac0127e4c95b8590f..5aba146300d38789d158bca0c5f1bc91a2ffde60 100644 (file)
--- 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 4e303cf7ead6dc7cf90e7e7545dda17ba849ad92..e233541d4c9f1ea1869bad7b78a42fc8a8efbc65 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8267,7 +8267,9 @@ 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;