[PATCH 2/2] drm: add DRIVER_RENDER_ONLY

[Christian König]

This allows to suppress creating the primary node. Useful for drivers
which don't expose any display functionality, but are render only by
design.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/drm_drv.c   | 10 ++++++----
 drivers/gpu/drm/drm_prime.c |  2 +-
 include/drm/drm_drv.h       |  7 +++++++
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index d81783f43452..4a525f78a932 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -634,9 +634,11 @@ static int drm_dev_init(struct drm_device *dev,
 			goto err;
 	}
 
-	ret = drm_minor_alloc(dev, DRM_MINOR_PRIMARY);
-	if (ret)
-		goto err;
+	if (!drm_core_check_feature(dev, DRIVER_RENDER_ONLY)) {
+		ret = drm_minor_alloc(dev, DRM_MINOR_PRIMARY);
+		if (ret)
+			goto err;
+	}
 
 	ret = drm_legacy_create_map_hash(dev);
 	if (ret)
@@ -902,7 +904,7 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
 		 driver->name, driver->major, driver->minor,
 		 driver->patchlevel, driver->date,
 		 dev->dev ? dev_name(dev->dev) : "virtual device",
-		 dev->primary->index);
+		 (dev->primary ?: dev->render)->index);
 
 	goto out_unlock;
 
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index a3f180653b8b..4afd3f15b135 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -740,7 +740,7 @@ int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
 	}
 
 	/* Used by drm_gem_mmap() to lookup the GEM object */
-	priv->minor = obj->dev->primary;
+	priv->minor = obj->dev->primary ?: obj->dev->render;
 	fil->private_data = priv;
 
 	ret = drm_vma_node_allow(&obj->vma_node, priv);
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index f6159acb8856..0a1450d47ca2 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -94,6 +94,13 @@ enum drm_driver_feature {
 	 * synchronization of command submission.
 	 */
 	DRIVER_SYNCOBJ_TIMELINE         = BIT(6),
+	/**
+	 * @DRIVER_RENDER_ONLY
+	 *
+	 * Driver is a render node only driver and don't want to support the
+	 * primary interface.
+	 */
+	DRIVER_RENDER_ONLY		= BIT(7),
 
 	/* IMPORTANT: Below are all the legacy flags, add new ones above. */
 
-- 
2.25.1