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authorLiviu Dudau <Liviu.Dudau@arm.com>2018-02-28 14:11:23 +0000
committerLiviu Dudau <Liviu.Dudau@arm.com>2018-06-20 15:30:20 +0100
commitd67b6a2065076d763c7df626b8c54f16038ad862 (patch)
treefb7d98ec56e8a726aa2ea0696c55b6702265729e
parentb13cc8dd588434e2aec781e6d12224e4c408ac18 (diff)
downloadlinux-d67b6a2065076d763c7df626b8c54f16038ad862.tar.gz
drm: writeback: Add client capability for exposing writeback connectors
Due to the fact that writeback connectors behave in a special way
in DRM (they always report being disconnected) we might confuse some
userspace. Add a client capability for writeback connectors that will
filter them out for clients that don't understand the capability.

Changelog:
 - only accept the capability if the client has already set the
DRM_CLIENT_CAP_ATOMIC one.

Cc: Sean Paul <seanpaul@chromium.org>
Cc: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Link: https://patchwork.freedesktop.org/patch/229038/
-rw-r--r--drivers/gpu/drm/drm_ioctl.c7
-rw-r--r--drivers/gpu/drm/drm_mode_config.c5
-rw-r--r--include/drm/drm_file.h7
-rw-r--r--include/uapi/drm/drm.h9
4 files changed, 28 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 0d4cfb232576..fe49fb0356b5 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -334,6 +334,13 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
 			return -EINVAL;
 		file_priv->aspect_ratio_allowed = req->value;
 		break;
+	case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:
+		if (!file_priv->atomic)
+			return -EINVAL;
+		if (req->value > 1)
+			return -EINVAL;
+		file_priv->writeback_connectors = req->value;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index e5c653357024..21e353bd3948 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -145,6 +145,11 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 	count = 0;
 	connector_id = u64_to_user_ptr(card_res->connector_id_ptr);
 	drm_for_each_connector_iter(connector, &conn_iter) {
+		/* only expose writeback connectors if userspace understands them */
+		if (!file_priv->writeback_connectors &&
+		    (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK))
+			continue;
+
 		if (drm_lease_held(file_priv, connector->base.id)) {
 			if (count < card_res->count_connectors &&
 			    put_user(connector->base.id, connector_id + count)) {
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 027ac16da3d1..26485acc51d7 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -193,6 +193,13 @@ struct drm_file {
 	unsigned aspect_ratio_allowed:1;
 
 	/**
+	 * @writeback_connectors:
+	 *
+	 * True if client understands writeback connectors
+	 */
+	unsigned writeback_connectors:1;
+
+	/**
 	 * @is_master:
 	 *
 	 * This client is the creator of @master. Protected by struct
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 9c660e1688ab..300f336633f2 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -687,6 +687,15 @@ struct drm_get_cap {
  */
 #define DRM_CLIENT_CAP_ASPECT_RATIO    4
 
+/**
+ * DRM_CLIENT_CAP_WRITEBACK_CONNECTORS
+ *
+ * If set to 1, the DRM core will expose special connectors to be used for
+ * writing back to memory the scene setup in the commit. Depends on client
+ * also supporting DRM_CLIENT_CAP_ATOMIC
+ */
+#define DRM_CLIENT_CAP_WRITEBACK_CONNECTORS	5
+
 /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
 struct drm_set_client_cap {
 	__u64 capability;