drm/i915: don't count cpu ports for fdi B/C lane sharing

This allows us to use all 4 fdi lanes on fdi B when the cpu eDP is
running on pipe C. Yay!

v2: Encapsulate test into a little helper function, as suggested by
Chris Wilson.

Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 1d157978f10b..1ef44b2a6952 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2369,6 +2369,11 @@ static void intel_fdi_normal_train(struct drm_crtc *crtc)
                            FDI_FE_ERRC_ENABLE);
 }
 
+static bool pipe_has_enabled_pch(struct intel_crtc *intel_crtc)
+{
+        return intel_crtc->base.enabled && intel_crtc->config.has_pch_encoder;
+}
+
 static void ivb_modeset_global_resources(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
@@ -2378,10 +2383,13 @@ static void ivb_modeset_global_resources(struct drm_device *dev)
                 to_intel_crtc(dev_priv->pipe_to_crtc_mapping[PIPE_C]);
         uint32_t temp;
 
-        /* When everything is off disable fdi C so that we could enable fdi B
-         * with all lanes. XXX: This misses the case where a pipe is not using
-         * any pch resources and so doesn't need any fdi lanes. */
-        if (!pipe_B_crtc->base.enabled && !pipe_C_crtc->base.enabled) {
+        /*
+         * When everything is off disable fdi C so that we could enable fdi B
+         * with all lanes. Note that we don't care about enabled pipes without
+         * an enabled pch encoder.
+         */
+        if (!pipe_has_enabled_pch(pipe_B_crtc) &&
+            !pipe_has_enabled_pch(pipe_C_crtc)) {
                 WARN_ON(I915_READ(FDI_RX_CTL(PIPE_B)) & FDI_RX_ENABLE);
                 WARN_ON(I915_READ(FDI_RX_CTL(PIPE_C)) & FDI_RX_ENABLE);
 
@@ -4015,7 +4023,7 @@ static bool ironlake_check_fdi_lanes(struct drm_device *dev, enum pipe pipe,
                 }
                 return true;
         case PIPE_C:
-                if (!pipe_B_crtc->base.enabled ||
+                if (!pipe_has_enabled_pch(pipe_B_crtc) ||
                     pipe_B_crtc->config.fdi_lanes <= 2) {
                         if (pipe_config->fdi_lanes > 2) {
                                 DRM_DEBUG_KMS("invalid shared fdi lane config on pipe %c: %i lanes\n",