drm/nouveau: add module option to disable TV detection

Intended to be used as a workaround in cases where we falsely detect
that a TV is connected when it's not.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -302,7 +302,7 @@ nouveau_connector_detect(struct drm_connector *connector)
 
 detect_analog:
 	nv_encoder = find_encoder_by_type(connector, OUTPUT_ANALOG);
-	if (!nv_encoder)
+	if (!nv_encoder && !nouveau_tv_disable)
 		nv_encoder = find_encoder_by_type(connector, OUTPUT_TV);
 	if (nv_encoder) {
 		struct drm_encoder *encoder = to_drm_encoder(nv_encoder);

drivers/gpu/drm/nouveau/nouveau_drv.c

@@ -87,6 +87,10 @@ MODULE_PARM_DESC(override_conntype, "Ignore DCB connector type");
 int nouveau_override_conntype = 0;
 module_param_named(override_conntype, nouveau_override_conntype, int, 0400);
 
+MODULE_PARM_DESC(tv_disable, "Disable TV-out detection\n");
+int nouveau_tv_disable = 0;
+module_param_named(tv_disable, nouveau_tv_disable, int, 0400);
+
 MODULE_PARM_DESC(tv_norm, "Default TV norm.\n"
 		 "\t\tSupported: PAL, PAL-M, PAL-N, PAL-Nc, NTSC-M, NTSC-J,\n"
 		 "\t\t\thd480i, hd480p, hd576i, hd576p, hd720p, hd1080i.\n"

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -682,6 +682,7 @@ extern int nouveau_uscript_tmds;
 extern int nouveau_vram_pushbuf;
 extern int nouveau_vram_notify;
 extern int nouveau_fbpercrtc;
+extern int nouveau_tv_disable;
 extern char *nouveau_tv_norm;
 extern int nouveau_reg_debug;
 extern char *nouveau_vbios;