drm: allow selecting a connector via -O

References: https://github.com/Plagman/gamescope/issues/211

src/drm.cpp

@@ -34,9 +34,36 @@ bool g_bRotated = false;
 
 bool g_bUseLayers = true;
 bool g_bDebugLayers = false;
+const char *g_sOutputName = nullptr;
 
 static int s_drm_log = 0;
 
+static std::map< uint32_t, const char * > connector_types = {
+	{ DRM_MODE_CONNECTOR_Unknown, "Unknown" },
+	{ DRM_MODE_CONNECTOR_VGA, "VGA" },
+	{ DRM_MODE_CONNECTOR_DVII, "DVI-I" },
+	{ DRM_MODE_CONNECTOR_DVID, "DVI-D" },
+	{ DRM_MODE_CONNECTOR_DVIA, "DVI-A" },
+	{ DRM_MODE_CONNECTOR_Composite, "Composite" },
+	{ DRM_MODE_CONNECTOR_SVIDEO, "SVIDEO" },
+	{ DRM_MODE_CONNECTOR_LVDS, "LVDS" },
+	{ DRM_MODE_CONNECTOR_Component, "Component" },
+	{ DRM_MODE_CONNECTOR_9PinDIN, "DIN" },
+	{ DRM_MODE_CONNECTOR_DisplayPort, "DisplayPort" },
+	{ DRM_MODE_CONNECTOR_HDMIA, "HDMI-A" },
+	{ DRM_MODE_CONNECTOR_HDMIB, "HDMI-B" },
+	{ DRM_MODE_CONNECTOR_TV, "TV" },
+	{ DRM_MODE_CONNECTOR_eDP, "eDP" },
+	{ DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" },
+	{ DRM_MODE_CONNECTOR_DSI, "DSI" },
+	{ DRM_MODE_CONNECTOR_DPI, "DPI" },
+	{ DRM_MODE_CONNECTOR_WRITEBACK, "Writeback" },
+	{ DRM_MODE_CONNECTOR_SPI, "SPI" },
+#ifdef DRM_MODE_CONNECTOR_USB
+	{ DRM_MODE_CONNECTOR_USB, "USB" },
+#endif
+};
+
 static struct crtc *find_crtc_for_encoder(struct drm_t *drm, const drmModeEncoder *encoder) {
 	for (size_t i = 0; i < drm->crtcs.size(); i++) {
 		/* possible_crtcs is a bitmask as described here:
@@ -314,6 +341,15 @@ static bool get_resources(struct drm_t *drm)
 			return false;
 		}
 
+		const char *type_str = "Unknown";
+		if ( connector_types.count( conn.connector->connector_type ) > 0 )
+			type_str = connector_types[ conn.connector->connector_type ];
+
+		char name[128] = {};
+		snprintf(name, sizeof(name), "%s-%d", type_str, conn.connector->connector_type_id);
+
+		conn.name = strdup(name);
+
 		drm->connectors.push_back(conn);
 	}
 
@@ -362,6 +398,23 @@ static bool get_resources(struct drm_t *drm)
 	return true;
 }
 
+static struct connector *find_connector( drm_t *drm, const char *name )
+{
+	for (size_t i = 0; i < drm->connectors.size(); i++) {
+		struct connector *conn = &drm->connectors[i];
+
+		if (conn->connector->connection != DRM_MODE_CONNECTED)
+			continue;
+
+		if ( name != nullptr && strcmp( conn->name, name ) != 0 )
+			continue;
+
+		return conn;
+	}
+
+	return nullptr;
+}
+
 static const drmModeModeInfo *get_matching_mode( const drmModeConnector *connector, int hdisplay, int vdisplay, uint32_t vrefresh )
 {
 	for (int i = 0; i < connector->count_modes; i++) {
@@ -436,20 +489,26 @@ int init_drm(struct drm_t *drm, const char *device)
 		return -1;
 	}
 
-	/* find a connected connector */
+	fprintf( stderr, "Connectors:\n" );
 	for (size_t i = 0; i < drm->connectors.size(); i++) {
-		if (drm->connectors[i].connector->connection == DRM_MODE_CONNECTED) {
-			drm->connector = &drm->connectors[i];
-			connector = drm->connector->connector;
-			break;
-		}
+		struct connector *conn = &drm->connectors[i];
+
+		const char *status_str = "disconnected";
+		if ( conn->connector->connection == DRM_MODE_CONNECTED )
+			status_str = "connected";
+
+		fprintf( stderr, "  %s (%s)\n", conn->name, status_str );
 	}
 
+	drm->connector = find_connector( drm, g_sOutputName );
 	if (!drm->connector) {
 		/* we could be fancy and listen for hotplug events and wait for
 		 * a connector..
 		 */
-		fprintf(stderr, "no connected connector!\n");
+		if ( g_sOutputName != nullptr )
+			fprintf( stderr, "Cannot find connector '%s'\n", g_sOutputName );
+		else
+			fprintf( stderr, "Cannot find any connector!\n" );
 		return -1;
 	}
 

src/drm.hpp

@@ -39,6 +39,7 @@ struct crtc {
 
 struct connector {
 	uint32_t id;
+	char *name;
 	drmModeConnector *connector;
 	std::map<std::string, drmModePropertyRes *> props;
 	std::map<std::string, uint64_t> initial_prop_values;
@@ -112,6 +113,7 @@ extern uint32_t g_nDRMFormat;
 extern bool g_bUseLayers;
 extern bool g_bRotated;
 extern bool g_bDebugLayers;
+extern const char *g_sOutputName;
 
 int init_drm(struct drm_t *drm, const char *device);
 int drm_atomic_commit(struct drm_t *drm, struct Composite_t *pComposite, struct VulkanPipeline_t *pPipeline );

src/main.cpp

@@ -97,6 +97,9 @@ int main(int argc, char **argv)
 			case 'f':
 				g_bFullscreen = true;
 				break;
+			case 'O':
+				g_sOutputName = optarg;
+				break;
 			default:
 				break;
 		}

src/main.hpp

@@ -1,6 +1,6 @@
 #pragma once
 
-#define GAMESCOPE_OPTIONS ":R:T:C:w:h:W:H:r:o:NFSvVecsdLnbfx"
+#define GAMESCOPE_OPTIONS ":R:T:C:w:h:W:H:r:o:NFSvVecsdLnbfxO:"
 
 int initOutput(void);