drm/ast: Set format registers in primary plane's update

The atomic modesetting code tried to distinguish format changes from
full modesetting operations. But the implementation was buggy and the
format registers were often updated even for simple pageflips.

Fix this problem by handling format changes in the primary plane's
update function.

v3:
	* program format in primary plane's update function
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200914072236.19398-2-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_mode.c

@@ -562,13 +562,24 @@ ast_primary_plane_helper_atomic_update(struct drm_plane *plane,
 	struct drm_plane_state *state = plane->state;
 	struct drm_gem_vram_object *gbo;
 	s64 gpu_addr;
+	struct drm_framebuffer *fb = state->fb;
+	struct drm_framebuffer *old_fb = old_state->fb;
+
+	if (!old_fb || (fb->format != old_fb->format)) {
+		struct drm_crtc_state *crtc_state = state->crtc->state;
+		struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc_state);
+		struct ast_vbios_mode_info *vbios_mode_info = &ast_crtc_state->vbios_mode_info;
+
+		ast_set_color_reg(ast, fb->format);
+		ast_set_vbios_color_reg(ast, fb->format, vbios_mode_info);
+	}
 
-	gbo = drm_gem_vram_of_gem(state->fb->obj[0]);
+	gbo = drm_gem_vram_of_gem(fb->obj[0]);
 	gpu_addr = drm_gem_vram_offset(gbo);
 	if (drm_WARN_ON_ONCE(dev, gpu_addr < 0))
 		return; /* Bug: we didn't pin the BO to VRAM in prepare_fb. */
 
-	ast_set_offset_reg(ast, state->fb);
+	ast_set_offset_reg(ast, fb);
 	ast_set_start_address_crt1(ast, (u32)gpu_addr);
 
 	ast_set_index_reg_mask(ast, AST_IO_SEQ_PORT, 0x1, 0xdf, 0x00);
@@ -733,6 +744,7 @@ static void ast_crtc_dpms(struct drm_crtc *crtc, int mode)
 static int ast_crtc_helper_atomic_check(struct drm_crtc *crtc,
 					struct drm_crtc_state *state)
 {
+	struct drm_device *dev = crtc->dev;
 	struct ast_crtc_state *ast_state;
 	const struct drm_format_info *format;
 	bool succ;
@@ -743,8 +755,8 @@ static int ast_crtc_helper_atomic_check(struct drm_crtc *crtc,
 	ast_state = to_ast_crtc_state(state);
 
 	format = ast_state->format;
-	if (!format)
-		return 0;
+	if (drm_WARN_ON_ONCE(dev, !format))
+		return -EINVAL; /* BUG: We didn't set format in primary check(). */
 
 	succ = ast_get_vbios_mode_info(format, &state->mode,
 				       &state->adjusted_mode,
@@ -768,27 +780,15 @@ static void ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
 {
 	struct drm_device *dev = crtc->dev;
 	struct ast_private *ast = to_ast_private(dev);
-	struct ast_crtc_state *ast_state;
-	const struct drm_format_info *format;
-	struct ast_vbios_mode_info *vbios_mode_info;
-	struct drm_display_mode *adjusted_mode;
+	struct drm_crtc_state *crtc_state = crtc->state;
+	struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc_state);
+	struct ast_vbios_mode_info *vbios_mode_info =
+		&ast_crtc_state->vbios_mode_info;
+	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
 
-	ast_state = to_ast_crtc_state(crtc->state);
-
-	format = ast_state->format;
-	if (!format)
-		return;
-
-	vbios_mode_info = &ast_state->vbios_mode_info;
-
-	ast_set_color_reg(ast, format);
-	ast_set_vbios_color_reg(ast, format, vbios_mode_info);
-
-	if (!crtc->state->mode_changed)
+	if (!drm_atomic_crtc_needs_modeset(crtc_state))
 		return;
 
-	adjusted_mode = &crtc->state->adjusted_mode;
-
 	ast_set_vbios_mode_reg(ast, adjusted_mode, vbios_mode_info);
 	ast_set_index_reg(ast, AST_IO_CRTC_PORT, 0xa1, 0x06);
 	ast_set_std_reg(ast, adjusted_mode, vbios_mode_info);