drm/i915: detect digital outputs on Haswell

Digital port detection on Haswell is indicated by the presence of a bit in
DDI_BUF_CTL for port A, and by a different register for ports B, C and D.
So we check for those bits during the initialization time and let the hdmi
function know about those.

Note that this bit does not indicates whether the output is DP or HDMI.
However, the DDI buffers can be programmed in a way that is shared between
DP/HDMI and FDI/HDMI except for PORT E.

So for now, we detect those digital outputs as being HDMI, but proper DP
support is still pending.

Note that DDI A can only drive eDP, so we do not handle it here for hdmi
initialization.

v2: simplify Haswell handling logic

v3: use generic function for handling digital outputs.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 20 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f1bb2e2ec173..1a06f97e73f8 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6474,7 +6474,26 @@ static void intel_setup_outputs(struct drm_device *dev)
 
         intel_crt_init(dev);
 
-        if (HAS_PCH_SPLIT(dev)) {
+        if (IS_HASWELL(dev)) {
+                int found;
+
+                /* Haswell uses DDI functions to detect digital outputs */
+                found = I915_READ(DDI_BUF_CTL_A) & DDI_INIT_DISPLAY_DETECTED;
+                /* DDI A only supports eDP */
+                if (found)
+                        intel_ddi_init(dev, PORT_A);
+
+                /* DDI B, C and D detection is indicated by the SFUSE_STRAP
+                 * register */
+                found = I915_READ(SFUSE_STRAP);
+
+                if (found & SFUSE_STRAP_DDIB_DETECTED)
+                        intel_ddi_init(dev, PORT_B);
+                if (found & SFUSE_STRAP_DDIC_DETECTED)
+                        intel_ddi_init(dev, PORT_C);
+                if (found & SFUSE_STRAP_DDID_DETECTED)
+                        intel_ddi_init(dev, PORT_D);
+        } else if (HAS_PCH_SPLIT(dev)) {
                 int found;
 
                 if (I915_READ(HDMIB) & PORT_DETECTED) {