eglfs/kms: Add drm atomic zpos property handling

This adds the ability to specify a ZPOS property for the eglfs plane
ZPOS will allow to control the relative position between eglfs layer
and the other layers.

It is bound to using QT_QPA_EGLFS_KMS_ZPOS environment variable to determine
its value.

Change-Id: I51986ccb22a9dbaeef20165ac5feb7dbe8047373
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

2 files changed, 3 insertions, 0 deletions

diff --git a/src/platformsupport/kmsconvenience/qkmsdevice.cpp b/src/platformsupport/kmsconvenience/qkmsdevice.cpp
index d477d12d72..71422b469b 100644
--- a/src/platformsupport/kmsconvenience/qkmsdevice.cpp
+++ b/src/platformsupport/kmsconvenience/qkmsdevice.cpp
@@ -824,6 +824,8 @@ void QKmsDevice::discoverPlanes()
                 plane.crtcXPropertyId = prop->prop_id;
             } else if (!strcasecmp(prop->name, "crtc_y")) {
                 plane.crtcYPropertyId = prop->prop_id;
+            } else if (!strcasecmp(prop->name, "zpos")) {
+                plane.zposPropertyId = prop->prop_id;
             }
         });
 
diff --git a/src/platformsupport/kmsconvenience/qkmsdevice_p.h b/src/platformsupport/kmsconvenience/qkmsdevice_p.h
index 5465cad941..403972fbb8 100644
--- a/src/platformsupport/kmsconvenience/qkmsdevice_p.h
+++ b/src/platformsupport/kmsconvenience/qkmsdevice_p.h
@@ -177,6 +177,7 @@ struct QKmsPlane
     uint32_t srcheightPropertyId = 0;
     uint32_t crtcwidthPropertyId = 0;
     uint32_t crtcheightPropertyId = 0;
+    uint32_t zposPropertyId = 0;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QKmsPlane::Rotations)