[RFC 1/5] drm: Add HDMI 2.0+ features exposing knob

[Jose Abreu]

We can't expect userspace to have full support for all HDMI 2.0+
features. Instead of expecting/waiting for userspace to support
the new features add a knob, much like the stereo knob, so that
DRM core will only expose the features when asked too.

Signed-off-by: Jose Abreu <joabreu at synopsys.com>
Cc: Carlos Palminha <palminha at synopsys.com>
Cc: dri-devel at lists.freedesktop.org
---
 drivers/gpu/drm/drm_ioctl.c | 5 +++++
 include/drm/drm_file.h      | 8 ++++++++
 include/uapi/drm/drm.h      | 7 +++++++
 3 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index a7c61c2..2430e2e 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -318,6 +318,11 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 		file_priv->atomic = req->value;
 		file_priv->universal_planes = req->value;
 		break;
+	case DRM_CLIENT_CAP_HDMI2:
+		if (req->value > 1)
+			return -EINVAL;
+		file_priv->hdmi2_allowed = req->value;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 5dd27ae..7b97d85 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -192,6 +192,14 @@ struct drm_file {
 	unsigned is_master:1;
 
 	/**
+	 * @hdmi2_allowed:
+	 *
+	 * True if client understands HDMI 2.0+ features like, for example,
+	 * extended aspect ratios
+	 */
+	unsigned hdmi2_allowed:1;
+
+	/**
 	 * @master:
 	 *
 	 * Master this node is currently associated with. Only relevant if
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index b2c5284..9e25138 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -678,6 +678,13 @@ struct drm_get_cap {
  */
 #define DRM_CLIENT_CAP_ATOMIC	3
 
+/**
+ * DRM_CLIENT_CAP_HDMI2
+ *
+ * If set to 1, the DRM core will expose HDMI 2.0+ features to userspace
+ */
+#define DRM_CLIENT_CAP_HDMI2	4
+
 /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
 struct drm_set_client_cap {
 	__u64 capability;
-- 
1.9.1