drm/i915/fbc: introduce struct intel_fbc_state_cache

Per the new atomic locking rules, we need to cache the CRTC, plane and
FB state structures we use so we can access them later without needing
more locks. So do this.

Notice that there are some pieces of the FBC code that look at things
that are only computed during the modeset, so we can't just can't
precompute whether FBC can be activated during the update_state_cache
stage. We may be able to do this later.
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453210558-7875-10-git-send-email-paulo.r.zanoni@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -917,6 +917,29 @@ struct intel_fbc {
 	bool enabled;
 	bool active;
 
+	struct intel_fbc_state_cache {
+		struct {
+			unsigned int mode_flags;
+			uint32_t hsw_bdw_pixel_rate;
+		} crtc;
+
+		struct {
+			unsigned int rotation;
+			int src_w;
+			int src_h;
+			bool visible;
+		} plane;
+
+		struct {
+			u64 ilk_ggtt_offset;
+			uint32_t id;
+			uint32_t pixel_format;
+			unsigned int stride;
+			int fence_reg;
+			unsigned int tiling_mode;
+		} fb;
+	} state_cache;
+
 	struct intel_fbc_reg_params {
 		struct {
 			enum pipe pipe;