drm/i915/sdvo: Always add a 30ms delay to make SDVO TV detection reliable

Commit d09c23de intended to add a 30ms delay to give the ADD time to
detect any TVs connected. However, it used the sdvo->is_tv flag to do so
which is dependent upon the previous detection result and not whether the
output supports TVs.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1377,10 +1377,12 @@ intel_sdvo_detect(struct drm_connector *connector, bool force)
 	if (!intel_sdvo_write_cmd(intel_sdvo,
 				  SDVO_CMD_GET_ATTACHED_DISPLAYS, NULL, 0))
 		return connector_status_unknown;
-	if (intel_sdvo->is_tv) {
-		/* add 30ms delay when the output type is SDVO-TV */
+
+	/* add 30ms delay when the output type might be TV */
+	if (intel_sdvo->caps.output_flags &
+	    (SDVO_OUTPUT_SVID0 | SDVO_OUTPUT_CVBS0))
 		mdelay(30);
-	}
+
 	if (!intel_sdvo_read_response(intel_sdvo, &response, 2))
 		return connector_status_unknown;