From: Keir Fraser <keir.fraser@citrix.com>
Date: Tue, 28 Jul 2009 15:47:37 +0000 (+0100)
Subject: ns16550: More robust check for presence of FIFO
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~13544
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=060cc4dbc77621d4f247bff1b4509a4f54a6feda;p=xen.git

ns16550: More robust check for presence of FIFO

Signed-off-by: Christoph Egger <Christoph.Egger@amd.com>
---

diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
index 1f88907008..7de7fcd386 100644
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -214,7 +214,8 @@ static void __devinit ns16550_init_preirq(struct serial_port *port)
     ns_write_reg(uart, FCR, FCR_ENABLE | FCR_CLRX | FCR_CLTX | FCR_TRG14);
 
     /* Check this really is a 16550+. Otherwise we have no FIFOs. */
-    if ( (ns_read_reg(uart, IIR) & 0xc0) == 0xc0 )
+    if ( ((ns_read_reg(uart, IIR) & 0xc0) == 0xc0) &&
+         ((ns_read_reg(uart, FCR) & FCR_TRG14) == FCR_TRG14) )
         port->tx_fifo_size = 16;
 }