[Intel-gfx] [PATCH v2 01/14] drm: Include the encoder itself in possible_clones

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

The docs say possible_clones should always include the encoder itself.
Since most drivers don't want to deal with the complexities of cloning
let's allow them to set possible_clones=0 and instead we'll fix that
up in the core.

We can't put this special case into drm_encoder_init() because drivers
will have to fill up possible_clones after adding all the relevant
encoders. Otherwise they wouldn't know the proper encoder indexes to
use. So we'll just do it just before registering the encoders.

TODO: Should we add the bit even if possible_clones was otherwise
populated by the driver?

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/drm_encoder.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/drm_encoder.c b/drivers/gpu/drm/drm_encoder.c
index 7fb47b7b8b44..e87e6fecc1fb 100644
--- a/drivers/gpu/drm/drm_encoder.c
+++ b/drivers/gpu/drm/drm_encoder.c
@@ -65,11 +65,26 @@ static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
 	{ DRM_MODE_ENCODER_DPI, "DPI" },
 };
 
+/*
+ * For some reason we want the encoder itself included in
+ * possible_clones. Make life easy for drivers by allowing them
+ * to leave possible_clones unset if no cloning is possible.
+ */
+static void fixup_possible_clones(struct drm_device *dev)
+{
+	struct drm_encoder *encoder;
+
+	drm_for_each_encoder(encoder, dev)
+		encoder->possible_clones |= drm_encoder_mask(encoder);
+}
+
 int drm_encoder_register_all(struct drm_device *dev)
 {
 	struct drm_encoder *encoder;
 	int ret = 0;
 
+	fixup_possible_clones(dev);
+
 	drm_for_each_encoder(encoder, dev) {
 		if (encoder->funcs->late_register)
 			ret = encoder->funcs->late_register(encoder);
-- 
2.21.0