drm: crtc_helper: Update hwmode before mode_set call

Just as we provide crtc->mode pre-populated with the requested mode,
move adjusted_mode into hwmode before we call the crtc's mode_set,
making sure to restore it on failure.

Allows drivers which thoughtlessly discard adjusted_mode in their
mode_set hooks (e.g. Exynos) to use hwmode directly, and also provides
some neat symmetry with crtc->mode.
Signed-off-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_crtc_helper.c

@@ -270,7 +270,7 @@ bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 			      struct drm_framebuffer *old_fb)
 {
 	struct drm_device *dev = crtc->dev;
-	struct drm_display_mode *adjusted_mode, saved_mode;
+	struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
 	struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 	struct drm_encoder_helper_funcs *encoder_funcs;
 	int saved_x, saved_y;
@@ -292,6 +292,7 @@ bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 	}
 
 	saved_mode = crtc->mode;
+	saved_hwmode = crtc->hwmode;
 	saved_x = crtc->x;
 	saved_y = crtc->y;
 
@@ -334,6 +335,8 @@ bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 	}
 	DRM_DEBUG_KMS("[CRTC:%d]\n", crtc->base.id);
 
+	crtc->hwmode = *adjusted_mode;
+
 	/* Prepare the encoders and CRTCs before setting the mode. */
 	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 
@@ -396,9 +399,6 @@ bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 			encoder->bridge->funcs->enable(encoder->bridge);
 	}
 
-	/* Store real post-adjustment hardware mode. */
-	crtc->hwmode = *adjusted_mode;
-
 	/* Calculate and store various constants which
 	 * are later needed by vblank and swap-completion
 	 * timestamping. They are derived from true hwmode.
@@ -411,6 +411,7 @@ bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 	if (!ret) {
 		crtc->enabled = saved_enabled;
 		crtc->mode = saved_mode;
+		crtc->hwmode = saved_hwmode;
 		crtc->x = saved_x;
 		crtc->y = saved_y;
 	}