From 181e5382e741c290d72010da9d6d74908e7b2d8f Mon Sep 17 00:00:00 2001
From: Paul Olav Tvete <paul.tvete@qt.io>
Date: Tue, 20 Aug 2019 10:12:53 +0200
Subject: [PATCH] eglfs/kms: Add drm atomic blend_op property handling

Add support for specifying the blend operation used when alpha-
blending KMS planes. Only available with atomic modesetting.
Set the environment variable QT_QPA_EGLFS_KMS_BLEND_OP to
the enum value of the 'blend_op' property.

Task-number: QTBUG-75659
Change-Id: If0ef5ba314b88adb530113b608d20fc9c027c5ec
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
---
 src/platformsupport/kmsconvenience/qkmsdevice.cpp              | 2 ++
 src/platformsupport/kmsconvenience/qkmsdevice_p.h              | 1 +
 .../eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp   | 3 +++
 3 files changed, 6 insertions(+)

diff --git a/src/platformsupport/kmsconvenience/qkmsdevice.cpp b/src/platformsupport/kmsconvenience/qkmsdevice.cpp
index 07ef60c5fff..d9d76c11467 100644
--- a/src/platformsupport/kmsconvenience/qkmsdevice.cpp
+++ b/src/platformsupport/kmsconvenience/qkmsdevice.cpp
@@ -854,6 +854,8 @@ void QKmsDevice::discoverPlanes()
                 plane.crtcYPropertyId = prop->prop_id;
             } else if (!strcasecmp(prop->name, "zpos")) {
                 plane.zposPropertyId = prop->prop_id;
+            } else if (!strcasecmp(prop->name, "blend_op")) {
+                plane.blendOpPropertyId = prop->prop_id;
             }
         });
 
diff --git a/src/platformsupport/kmsconvenience/qkmsdevice_p.h b/src/platformsupport/kmsconvenience/qkmsdevice_p.h
index 403972fbb8f..77070c293d7 100644
--- a/src/platformsupport/kmsconvenience/qkmsdevice_p.h
+++ b/src/platformsupport/kmsconvenience/qkmsdevice_p.h
@@ -178,6 +178,7 @@ struct QKmsPlane
     uint32_t crtcwidthPropertyId = 0;
     uint32_t crtcheightPropertyId = 0;
     uint32_t zposPropertyId = 0;
+    uint32_t blendOpPropertyId = 0;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(QKmsPlane::Rotations)
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp
index 09a10bcc9cd..2034632fb33 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp
@@ -331,6 +331,9 @@ void QEglFSKmsGbmScreen::flip()
             static int zpos = qEnvironmentVariableIntValue("QT_QPA_EGLFS_KMS_ZPOS");
             if (zpos)
                 drmModeAtomicAddProperty(request, op.eglfs_plane->id, op.eglfs_plane->zposPropertyId, zpos);
+            static uint blendOp = uint(qEnvironmentVariableIntValue("QT_QPA_EGLFS_KMS_BLEND_OP"));
+            if (blendOp)
+                drmModeAtomicAddProperty(request, op.eglfs_plane->id, op.eglfs_plane->blendOpPropertyId, blendOp);
         }
 #endif
     } else {