drm/i915: Simplify return value from intel_get_load_detect_pipe

... and so remove the confusion as to whether to use the returned crtc
or intel_encoder->base.crtc with the subsequent load-detection. Even
though they were the same, the two instances of load-detection code
disagreed over which was the more correct.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/intel_crt.c

@@ -305,13 +305,11 @@ static bool intel_crt_detect_ddc(struct drm_connector *connector)
 }
 
 static enum drm_connector_status
-intel_crt_load_detect(struct drm_crtc *crtc, struct intel_crt *crt)
+intel_crt_load_detect(struct intel_crt *crt)
 {
-	struct drm_encoder *encoder = &crt->base.base;
+	struct drm_device *dev = crt->base.base.dev;
-	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	uint32_t pipe = to_intel_crtc(crt->base.base.crtc)->pipe;
-	uint32_t pipe = intel_crtc->pipe;
 	uint32_t save_bclrpat;
 	uint32_t save_vtotal;
 	uint32_t vtotal, vactive;
@@ -454,15 +452,14 @@ intel_crt_detect(struct drm_connector *connector, bool force)
 	/* for pre-945g platforms use load detect */
 	crtc = crt->base.base.crtc;
 	if (crtc && crtc->enabled) {
-		status = intel_crt_load_detect(crtc, crt);
+		status = intel_crt_load_detect(crt);
 	} else {
-		crtc = intel_get_load_detect_pipe(&crt->base, connector,
+		if (intel_get_load_detect_pipe(&crt->base, connector,
-						  NULL, &dpms_mode);
+					       NULL, &dpms_mode)) {
-		if (crtc) {
 			if (intel_crt_detect_ddc(connector))
 				status = connector_status_connected;
 			else
-				status = intel_crt_load_detect(crtc, crt);
+				status = intel_crt_load_detect(crt);
 			intel_release_load_detect_pipe(&crt->base,
 						       connector, dpms_mode);
 		} else

drivers/gpu/drm/i915/intel_display.c

@@ -5481,7 +5481,7 @@ static struct drm_display_mode load_detect_mode = {
 		 704, 832, 0, 480, 489, 491, 520, 0, DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC),
 };
 
-struct drm_crtc *intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
+bool intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
 				struct drm_connector *connector,
 				struct drm_display_mode *mode,
 				int *dpms_mode)
@@ -5517,7 +5517,7 @@ struct drm_crtc *intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
 			crtc_funcs->dpms(crtc, DRM_MODE_DPMS_ON);
 			encoder_funcs->dpms(encoder, DRM_MODE_DPMS_ON);
 		}
-		return crtc;
+		return true;
 	}
 
 	/* Find an unused one (if possible) */
@@ -5537,7 +5537,8 @@ struct drm_crtc *intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
 	 * If we didn't find an unused CRTC, don't use any.
 	 */
 	if (!crtc) {
-		return NULL;
+		DRM_DEBUG_KMS("no pipe available for load-detect\n");
+		return false;
 	}
 
 	encoder->crtc = crtc;
@@ -5561,10 +5562,11 @@ struct drm_crtc *intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
 		encoder_funcs->mode_set(encoder, &crtc->mode, &crtc->mode);
 		encoder_funcs->commit(encoder);
 	}
+
 	/* let the connector get through one full cycle before testing */
 	intel_wait_for_vblank(dev, intel_crtc->pipe);
 
-	return crtc;
+	return true;
 }
 
 void intel_release_load_detect_pipe(struct intel_encoder *intel_encoder,

drivers/gpu/drm/i915/intel_drv.h

@@ -291,7 +291,7 @@ int intel_get_pipe_from_crtc_id(struct drm_device *dev, void *data,
 				struct drm_file *file_priv);
 extern void intel_wait_for_vblank(struct drm_device *dev, int pipe);
 extern void intel_wait_for_pipe_off(struct drm_device *dev, int pipe);
-extern struct drm_crtc *intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
+extern bool intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
 				       struct drm_connector *connector,
 				       struct drm_display_mode *mode,
 				       int *dpms_mode);

drivers/gpu/drm/i915/intel_tv.c

@@ -1361,12 +1361,10 @@ intel_tv_detect(struct drm_connector *connector, bool force)
 	if (intel_tv->base.base.crtc && intel_tv->base.base.crtc->enabled) {
 		type = intel_tv_detect_type(intel_tv, connector);
 	} else if (force) {
-		struct drm_crtc *crtc;
 		int dpms_mode;
 
-		crtc = intel_get_load_detect_pipe(&intel_tv->base, connector,
+		if (intel_get_load_detect_pipe(&intel_tv->base, connector,
-						  &mode, &dpms_mode);
+					       &mode, &dpms_mode)) {
-		if (crtc) {
 			type = intel_tv_detect_type(intel_tv, connector);
 			intel_release_load_detect_pipe(&intel_tv->base, connector,
 						       dpms_mode);