drm/i915: Store the initial framebuffer in initial_plane_config

At the moment we use crtc->base.primary->fb to hold the initial
framebuffer allocation, disregarding if it's valid or not.

This lead to believe we were actually updating the fb at this point, but
it's not true and we haven't even called drm_framebuffer_init() on this
fb.

Instead, let's store the state in struct intel_initial_plane_config
until we know we can reuse that framebuffer.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -2371,7 +2371,7 @@ intel_alloc_plane_obj(struct intel_crtc *crtc,
 	struct drm_device *dev = crtc->base.dev;
 	struct drm_i915_gem_object *obj = NULL;
 	struct drm_mode_fb_cmd2 mode_cmd = { 0 };
-	struct drm_framebuffer *fb = crtc->base.primary->fb;
+	struct drm_framebuffer *fb = &plane_config->fb->base;
 	u32 base = plane_config->base;
 
 	if (plane_config->size == 0)
@@ -2435,16 +2435,16 @@ intel_find_plane_obj(struct intel_crtc *intel_crtc,
 	struct intel_crtc *i;
 	struct drm_i915_gem_object *obj;
 
-	if (!intel_crtc->base.primary->fb)
+	if (!plane_config->fb)
 		return;
 
 	if (intel_alloc_plane_obj(intel_crtc, plane_config)) {
+		intel_crtc->base.primary->fb = &plane_config->fb->base;
 		update_state_fb(intel_crtc->base.primary);
 		return;
 	}
 
-	kfree(intel_crtc->base.primary->fb);
-	intel_crtc->base.primary->fb = NULL;
+	kfree(plane_config->fb);
 
 	/*
 	 * Failed to alloc the obj, check to see if we should share
@@ -6653,7 +6653,7 @@ i9xx_get_initial_plane_config(struct intel_crtc *crtc,
 		      fb->bits_per_pixel, base, fb->pitches[0],
 		      plane_config->size);
 
-	crtc->base.primary->fb = fb;
+	plane_config->fb = intel_fb;
 }
 
 static void chv_crtc_clock_get(struct intel_crtc *crtc,
@@ -7690,7 +7690,7 @@ skylake_get_initial_plane_config(struct intel_crtc *crtc,
 		      fb->bits_per_pixel, base, fb->pitches[0],
 		      plane_config->size);
 
-	crtc->base.primary->fb = fb;
+	plane_config->fb = intel_fb;
 	return;
 
 error:
@@ -7781,7 +7781,7 @@ ironlake_get_initial_plane_config(struct intel_crtc *crtc,
 		      fb->bits_per_pixel, base, fb->pitches[0],
 		      plane_config->size);
 
-	crtc->base.primary->fb = fb;
+	plane_config->fb = intel_fb;
 }
 
 static bool ironlake_get_pipe_config(struct intel_crtc *crtc,

drivers/gpu/drm/i915/intel_drv.h

@@ -258,6 +258,7 @@ struct intel_plane_state {
 };
 
 struct intel_initial_plane_config {
+	struct intel_framebuffer *fb;
 	unsigned int tiling;
 	int size;
 	u32 base;