[PATCH v4 12/12] drm/ast: Implement polling for VGA and SIL164 connectors

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Implement polling for VGA and SIL164 connectors. Set the flag
DRM_CONNECTOR_POLL_DISCONNECT for each to detect the removal of the
monitor cable. Implement struct drm_connector_helper_funcs.detect_ctx
for each type of connector by testing for EDID data. The code for
both types of connectors is identical for now. Maybe this can later
become a common helper function for various drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
 drivers/gpu/drm/ast/ast_mode.c | 36 ++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 71cc681d6188f..f740b8706a38b 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1344,8 +1344,24 @@ static int ast_crtc_init(struct drm_device *dev)
  * VGA Connector
  */
 
+static int ast_vga_connector_helper_detect_ctx(struct drm_connector *connector,
+					       struct drm_modeset_acquire_ctx *ctx,
+					       bool force)
+{
+	enum drm_connector_status status = connector_status_disconnected;
+	const struct drm_edid *edid;
+
+	edid = drm_edid_read(connector);
+	if (edid)
+		status = connector_status_connected;
+	drm_edid_free(edid);
+
+	return status;
+}
+
 static const struct drm_connector_helper_funcs ast_vga_connector_helper_funcs = {
 	.get_modes = drm_connector_helper_get_modes,
+	.detect_ctx = ast_vga_connector_helper_detect_ctx,
 };
 
 static const struct drm_connector_funcs ast_vga_connector_funcs = {
@@ -1379,7 +1395,7 @@ static int ast_vga_connector_init(struct drm_device *dev, struct drm_connector *
 	connector->interlace_allowed = 0;
 	connector->doublescan_allowed = 0;
 
-	connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	connector->polled = DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
 
 	return 0;
 }
@@ -1412,8 +1428,24 @@ static int ast_vga_output_init(struct ast_device *ast)
  * SIL164 Connector
  */
 
+static int ast_sil164_connector_helper_detect_ctx(struct drm_connector *connector,
+						  struct drm_modeset_acquire_ctx *ctx,
+						  bool force)
+{
+	enum drm_connector_status status = connector_status_disconnected;
+	const struct drm_edid *edid;
+
+	edid = drm_edid_read(connector);
+	if (edid)
+		status = connector_status_connected;
+	drm_edid_free(edid);
+
+	return status;
+}
+
 static const struct drm_connector_helper_funcs ast_sil164_connector_helper_funcs = {
 	.get_modes = drm_connector_helper_get_modes,
+	.detect_ctx = ast_sil164_connector_helper_detect_ctx,
 };
 
 static const struct drm_connector_funcs ast_sil164_connector_funcs = {
@@ -1447,7 +1479,7 @@ static int ast_sil164_connector_init(struct drm_device *dev, struct drm_connecto
 	connector->interlace_allowed = 0;
 	connector->doublescan_allowed = 0;
 
-	connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	connector->polled = DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
 
 	return 0;
 }
-- 
2.44.0