fbdev: correct tests on unsigned

index 756efeb..4f576bb 100644
@@ -393,8 +393,10 @@ static void fb_do_show_logo(struct fb_info *info, struct fb_image *image,
 			image->dx += image->width + 8;
 		}
 	} else if (rotate == FB_ROTATE_UD) {
-		for (x = 0; x < num && image->dx >= 0; x++) {
+		for (x = 0; x < num; x++) {
 			info->fbops->fb_imageblit(info, image);
+			if (image->dx < image->width + 8)
+				break;
 			image->dx -= image->width + 8;
 		}
 	} else if (rotate == FB_ROTATE_CW) {

@@ -405,8 +407,10 @@ static void fb_do_show_logo(struct fb_info *info, struct fb_image *image,
 			image->dy += image->height + 8;
 		}
 	} else if (rotate == FB_ROTATE_CCW) {
-		for (x = 0; x < num && image->dy >= 0; x++) {
+		for (x = 0; x < num; x++) {
 			info->fbops->fb_imageblit(info, image);
+			if (image->dx < image->width + 8)
+				break;
 			image->dy -= image->height + 8;
 		}
 	}

@@ -1094,7 +1098,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
 			ret = -EINVAL;
 			break;
 		}
-		if (con2fb.framebuffer < 0 || con2fb.framebuffer >= FB_MAX) {
+		if (con2fb.framebuffer >= FB_MAX) {
 			ret = -EINVAL;
 			break;
 		}