We want to enable/test plane updates via the atomic interface, but as
soon as we flip DRIVER_ATOMIC on, the DRM core will take some atomic
codepaths to lookup properties during drmModeGetConnector() and some of
those codepaths unconditionally dereference connector->state
(specifically when looking up the CRTC ID property in
drm_atomic_connector_get_property()).  Create a dummy connector state
for each connector at init time to ensure the DRM core doesn't try to
dereference a NULL connector->state.  The actual connector properties
will never be updated or contain useful information, but since we're
doing this specifically for testing/debug of the plane operations (and
only when a specific kernel module option is given), that shouldn't
really matter.

Signed-off-by: Matt Roper <matthew.d.ro...@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c 
b/drivers/gpu/drm/i915/intel_display.c
index 0e18879..82defd3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12368,6 +12368,7 @@ static void intel_setup_outputs(struct drm_device *dev)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_encoder *encoder;
+       struct drm_connector *connector;
        bool dpd_is_edp = false;
 
        intel_lvds_init(dev);
@@ -12498,6 +12499,33 @@ static void intel_setup_outputs(struct drm_device *dev)
        if (SUPPORTS_TV(dev))
                intel_tv_init(dev);
 
+       /*
+        * FIXME:  We don't have full atomic support yet, but we want to be
+        * able to enable/test plane updates via the atomic interface in the
+        * meantime.  However as soon as we flip DRIVER_ATOMIC on, the DRM core
+        * will take some atomic codepaths to lookup properties during
+        * drmModeGetConnector() that unconditionally dereference
+        * connector->state.
+        *
+        * We create a dummy connector state here for each connector to ensure
+        * the DRM core doesn't try to dereference a NULL connector->state.
+        * The actual connector properties will never be updated or contain
+        * useful information, but since we're doing this specifically for
+        * testing/debug of the plane operations (and only when a specific
+        * kernel module option is given), that shouldn't really matter.
+        *
+        * Once atomic support for crtc's + connectors lands, this loop should
+        * be removed since we'll be setting up real connector state, which
+        * will contain Intel-specific properties.
+        */
+       list_for_each_entry(connector,
+                           &dev->mode_config.connector_list,
+                           head) {
+               if (!WARN_ON(connector->state))
+                       connector->state = kzalloc(sizeof(*connector->state),
+                                                  GFP_KERNEL);
+       }
+
        intel_psr_init(dev);
 
        for_each_intel_encoder(dev, encoder) {
-- 
1.8.5.1

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