drm/i915: Allow sprites to be configured on a disabled pipe

We allow cursors to be set up when the pipe is disabled. Do the same for
sprites as well.

We need to be somewhat careful with the primary disable logic as we
don't want to accidentally enable the primary plane on a disabled pipe.

v2: Skip primary enable/disable and plane registers
    writes on disabled pipe
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_sprite.c

@@ -623,14 +623,10 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		   uint32_t src_w, uint32_t src_h)
 {
 	struct drm_device *dev = plane->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct intel_plane *intel_plane = to_intel_plane(plane);
 	struct intel_framebuffer *intel_fb;
 	struct drm_i915_gem_object *obj, *old_obj;
-	int pipe = intel_plane->pipe;
-	enum transcoder cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv,
-								      pipe);
 	int ret = 0;
 	bool disable_primary = false;
 	bool visible;
@@ -652,8 +648,8 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		.y2 = crtc_y + crtc_h,
 	};
 	const struct drm_rect clip = {
-		.x2 = intel_crtc->config.pipe_src_w,
-		.y2 = intel_crtc->config.pipe_src_h,
+		.x2 = intel_crtc->active ? intel_crtc->config.pipe_src_w : 0,
+		.y2 = intel_crtc->active ? intel_crtc->config.pipe_src_h : 0,
 	};
 
 	intel_fb = to_intel_framebuffer(fb);
@@ -670,12 +666,6 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	intel_plane->src_w = src_w;
 	intel_plane->src_h = src_h;
 
-	/* Pipe must be running... */
-	if (!(I915_READ(PIPECONF(cpu_transcoder)) & PIPECONF_ENABLE)) {
-		DRM_DEBUG_KMS("Pipe disabled\n");
-		return -EINVAL;
-	}
-
 	/* Don't modify another pipe's plane */
 	if (intel_plane->pipe != intel_crtc->pipe) {
 		DRM_DEBUG_KMS("Wrong plane <-> crtc mapping\n");
@@ -810,7 +800,7 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	 * we can disable the primary and save power.
 	 */
 	disable_primary = drm_rect_equals(&dst, &clip);
-	WARN_ON(disable_primary && !visible);
+	WARN_ON(disable_primary && !visible && intel_crtc->active);
 
 	mutex_lock(&dev->struct_mutex);
 
@@ -825,6 +815,7 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 
 	intel_plane->obj = obj;
 
+	if (intel_crtc->active) {
 		/*
 		 * Be sure to re-enable the primary before the sprite is no longer
 		 * covering it fully.
@@ -841,6 +832,7 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 
 		if (disable_primary)
 			intel_disable_primary(crtc);
+	}
 
 	/* Unpin old obj after new one is active to avoid ugliness */
 	if (old_obj) {
@@ -852,6 +844,7 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		 */
 		if (old_obj != obj) {
 			mutex_unlock(&dev->struct_mutex);
+			if (intel_crtc->active)
 				intel_wait_for_vblank(dev, to_intel_crtc(crtc)->pipe);
 			mutex_lock(&dev->struct_mutex);
 		}
@@ -868,6 +861,7 @@ intel_disable_plane(struct drm_plane *plane)
 {
 	struct drm_device *dev = plane->dev;
 	struct intel_plane *intel_plane = to_intel_plane(plane);
+	struct intel_crtc *intel_crtc;
 	int ret = 0;
 
 	if (!plane->fb)
@@ -876,12 +870,17 @@ intel_disable_plane(struct drm_plane *plane)
 	if (WARN_ON(!plane->crtc))
 		return -EINVAL;
 
+	intel_crtc = to_intel_crtc(plane->crtc);
+
+	if (intel_crtc->active) {
 		intel_enable_primary(plane->crtc);
 		intel_plane->disable_plane(plane, plane->crtc);
+	}
 
 	if (!intel_plane->obj)
 		goto out;
 
+	if (intel_crtc->active)
 		intel_wait_for_vblank(dev, intel_plane->pipe);
 
 	mutex_lock(&dev->struct_mutex);