drm/vmwgfx: Prune modes based on available VRAM size

This needs to be reviewed once we support screen objects and don't rely
on VRAM for the frame-buffer.

Also fix some integer overflow issues pointed out by Michel Daenzer.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
index 11cb39e..a01c47d 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c
@@ -427,7 +427,9 @@
 {
 	struct vmw_legacy_display_unit *ldu = vmw_connector_to_ldu(connector);
 	struct drm_device *dev = connector->dev;
+	struct vmw_private *dev_priv = vmw_priv(dev);
 	struct drm_display_mode *mode = NULL;
+	struct drm_display_mode *bmode;
 	struct drm_display_mode prefmode = { DRM_MODE("preferred",
 		DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED,
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -443,22 +445,30 @@
 		mode->hdisplay = ldu->pref_width;
 		mode->vdisplay = ldu->pref_height;
 		mode->vrefresh = drm_mode_vrefresh(mode);
-		drm_mode_probed_add(connector, mode);
+		if (vmw_kms_validate_mode_vram(dev_priv, mode->hdisplay * 2,
+					       mode->vdisplay)) {
+			drm_mode_probed_add(connector, mode);
 
-		if (ldu->pref_mode) {
-			list_del_init(&ldu->pref_mode->head);
-			drm_mode_destroy(dev, ldu->pref_mode);
+			if (ldu->pref_mode) {
+				list_del_init(&ldu->pref_mode->head);
+				drm_mode_destroy(dev, ldu->pref_mode);
+			}
+
+			ldu->pref_mode = mode;
 		}
-
-		ldu->pref_mode = mode;
 	}
 
 	for (i = 0; vmw_ldu_connector_builtin[i].type != 0; i++) {
-		if (vmw_ldu_connector_builtin[i].hdisplay > max_width ||
-		    vmw_ldu_connector_builtin[i].vdisplay > max_height)
+		bmode = &vmw_ldu_connector_builtin[i];
+		if (bmode->hdisplay > max_width ||
+		    bmode->vdisplay > max_height)
 			continue;
 
-		mode = drm_mode_duplicate(dev, &vmw_ldu_connector_builtin[i]);
+		if (!vmw_kms_validate_mode_vram(dev_priv, bmode->hdisplay * 2,
+						bmode->vdisplay))
+			continue;
+
+		mode = drm_mode_duplicate(dev, bmode);
 		if (!mode)
 			return 0;
 		mode->vrefresh = drm_mode_vrefresh(mode);