drm/i915: track is_dual_link in intel_lvds

Yeah, all users (both the clock selection special cases and the lvds
pin pair stuff) are still in common code, but this will change.

v2: Rebase on top of Jani Nikula's panel rework.

v3: Incorporate review from Paulo Zanoni:
- s/__is_dual_link_lvds/compute_is_dual_link_lvds
- kill dev_priv->lvds_val
- drop spurious whitespace change

v4: Add a debug printk to display the dual-link status, as suggested
by Paulo Zanoni in review.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> (v3)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 31 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 4158a8839433..31fdbfd48e44 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -52,6 +52,7 @@ struct intel_lvds_encoder {
         u32 pfit_control;
         u32 pfit_pgm_ratios;
         bool pfit_dirty;
+        bool is_dual_link;
 
         struct intel_lvds_connector *attached_connector;
 };
@@ -923,6 +924,23 @@ static const struct dmi_system_id intel_dual_link_lvds[] = {
 
 bool intel_is_dual_link_lvds(struct drm_device *dev)
 {
+        struct intel_encoder *encoder;
+        struct intel_lvds_encoder *lvds_encoder;
+
+        list_for_each_entry(encoder, &dev->mode_config.encoder_list,
+                            base.head) {
+                if (encoder->type == INTEL_OUTPUT_LVDS) {
+                        lvds_encoder = to_lvds_encoder(&encoder->base);
+
+                        return lvds_encoder->is_dual_link;
+                }
+        }
+
+        return false;
+}
+
+static bool compute_is_dual_link_lvds(struct drm_device *dev)
+{
         unsigned int val;
         struct drm_i915_private *dev_priv = dev->dev_private;
         u32 lvds_reg;
@@ -940,19 +958,15 @@ bool intel_is_dual_link_lvds(struct drm_device *dev)
         if (dmi_check_system(intel_dual_link_lvds))
                 return true;
 
-        if (dev_priv->lvds_val)
-                val = dev_priv->lvds_val;
-        else {
-                /* BIOS should set the proper LVDS register value at boot, but
-                 * in reality, it doesn't set the value when the lid is closed;
-                 * we need to check "the value to be set" in VBT when LVDS
-                 * register is uninitialized.
-                 */
-                val = I915_READ(lvds_reg);
-                if (!(val & ~(LVDS_PIPE_MASK | LVDS_DETECTED)))
-                        val = dev_priv->bios_lvds_val;
-                dev_priv->lvds_val = val;
-        }
+        /* BIOS should set the proper LVDS register value at boot, but
+         * in reality, it doesn't set the value when the lid is closed;
+         * we need to check "the value to be set" in VBT when LVDS
+         * register is uninitialized.
+         */
+        val = I915_READ(lvds_reg);
+        if (!(val & ~(LVDS_PIPE_MASK | LVDS_DETECTED)))
+                val = dev_priv->bios_lvds_val;
+
         return (val & LVDS_CLKB_POWER_MASK) == LVDS_CLKB_POWER_UP;
 }
 
@@ -1162,6 +1176,10 @@ bool intel_lvds_init(struct drm_device *dev)
                 goto failed;
 
 out:
+        lvds_encoder->is_dual_link = compute_is_dual_link_lvds(dev);
+        DRM_DEBUG_KMS("detected %s-link lvds configuration\n",
+                      lvds_encoder->is_dual_link ? "dual" : "single");
+
         /*
          * Unlock registers and just
          * leave them unlocked