drm/i915: Report the origin of the LVDS fixed panel mode

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: resolve conflict around the call to intel_crtc_mode_get. And
add the missing NULL check Chris spotted while at it.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 2e266277f035..81502e8be26b 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -1056,14 +1056,23 @@ bool intel_lvds_init(struct drm_device *dev)
 
         list_for_each_entry(scan, &connector->probed_modes, head) {
                 if (scan->type & DRM_MODE_TYPE_PREFERRED) {
+                        DRM_DEBUG_KMS("using preferred mode from EDID: ");
+                        drm_mode_debug_printmodeline(scan);
+
                         fixed_mode = drm_mode_duplicate(dev, scan);
-                        intel_find_lvds_downclock(dev, fixed_mode, connector);
-                        goto out;
+                        if (fixed_mode) {
+                                intel_find_lvds_downclock(dev, fixed_mode,
+                                                          connector);
+                                goto out;
+                        }
                 }
         }
 
         /* Failed to get EDID, what about VBT? */
         if (dev_priv->lfp_lvds_vbt_mode) {
+                DRM_DEBUG_KMS("using mode from VBT: ");
+                drm_mode_debug_printmodeline(dev_priv->lfp_lvds_vbt_mode);
+
                 fixed_mode = drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
                 if (fixed_mode) {
                         fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
@@ -1088,6 +1097,8 @@ bool intel_lvds_init(struct drm_device *dev)
         if (crtc && (lvds & LVDS_PORT_EN)) {
                 fixed_mode = intel_crtc_mode_get(dev, crtc);
                 if (fixed_mode) {
+                        DRM_DEBUG_KMS("using current (BIOS) mode: ");
+                        drm_mode_debug_printmodeline(fixed_mode);
                         fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
                         goto out;
                 }