SpriteFont on linux produce black squares

Dear, i use a spritefont ARIAL and in a sample project for linux when i
use DrawString of spritebatch it draw black squares and not the letter.

I have used spritebatch Begin with varius parameter but nothing

can some one help me ?

This is the simple source code:

    using System;

  using Microsoft.Xna.Framework;
    using Microsoft.Xna.Framework.Graphics;
     using Microsoft.Xna.Framework.Storage;
       using Microsoft.Xna.Framework.Input;



     namespace testfont
    {
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Game
{
	GraphicsDeviceManager graphics;
	SpriteBatch spriteBatch;
	SpriteFont spriteFont;

	public Game1 ()
	{
		graphics = new GraphicsDeviceManager (this);
		Content.RootDirectory = "Content";	            
		graphics.IsFullScreen = false;		
	}

	/// <summary>
	/// Allows the game to perform any initialization it needs to before starting to run.
	/// This is where it can query for any required services and load any non-graphic
	/// related content.  Calling base.Initialize will enumerate through any components
	/// and initialize them as well.
	/// </summary>
	protected override void Initialize ()
	{
		// TODO: Add your initialization logic here
		base.Initialize ();
			
	}

	/// <summary>
	/// LoadContent will be called once per game and is the place to load
	/// all of your content.
	/// </summary>
	protected override void LoadContent ()
	{
		// Create a new SpriteBatch, which can be used to draw textures.
		spriteBatch = new SpriteBatch (GraphicsDevice);

		//TODO: use this.Content to load your game content here 

		 spriteFont =  Content.Load<SpriteFont> ("miofont");

	}

	/// <summary>
	/// Allows the game to run logic such as updating the world,
	/// checking for collisions, gathering input, and playing audio.
	/// </summary>
	/// <param name="gameTime">Provides a snapshot of timing values.</param>
	protected override void Update (GameTime gameTime)
	{
		// For Mobile devices, this logic will close the Game when the Back button is pressed
		if (GamePad.GetState (PlayerIndex.One).Buttons.Back == ButtonState.Pressed) {
			Exit ();
		}
		// TODO: Add your update logic here			
		base.Update (gameTime);
	}

	/// <summary>
	/// This is called when the game should draw itself.
	/// </summary>
	/// <param name="gameTime">Provides a snapshot of timing values.</param>
	protected override void Draw (GameTime gameTime)
	{
		graphics.GraphicsDevice.Clear (Color.CornflowerBlue);
	
		//TODO: Add your drawing code here


		//spriteBatch.Begin ();
		spriteBatch.Begin(0,BlendState.Opaque); 
		spriteBatch.DrawString (spriteFont, "Ciaooooooooo", new Vector2 (100, 100), Color.White);
		spriteBatch.DrawString (spriteFont, "AAAAAAAAAAAA", new Vector2 (200, 200), Color.Red);
		spriteBatch.End ();
		base.Draw (gameTime);
	}
}
    }

Did you manage to find a solution? I’m having the same problem

Dear,
i found only this workaround :
Transform it to sprite graphics