[hpoussin] 14631: Allow interrupts indicating an empty buffer only if some bytes are pending

Allow interrupts indicating an empty buffer only if some bytes are
pending
This should correct the boot in Qemu
Modified: trunk/reactos/drivers/dd/serial/misc.c
  _____  

Modified: trunk/reactos/drivers/dd/serial/misc.c
--- trunk/reactos/drivers/dd/serial/misc.c	2005-04-15 22:02:37 UTC
(rev 14630)
+++ trunk/reactos/drivers/dd/serial/misc.c	2005-04-15 22:14:13 UTC
(rev 14631)
@@ -130,11 +130,13 @@

 			DeviceExtension->ComPort, Byte);
 		DeviceExtension->SerialPerfStats.TransmittedCount++;
 	}
+	if (!IsCircularBufferEmpty(&DeviceExtension->OutputBuffer))
+	{
+		/* allow new interrupts */
+		IER = READ_PORT_UCHAR(SER_IER(ComPortBase));
+		WRITE_PORT_UCHAR(SER_IER(ComPortBase), IER |
SR_IER_THR_EMPTY);
+	}
 	KeReleaseSpinLock(&DeviceExtension->OutputBufferLock, Irql);
-	
-	/* allow new interrupts */
-	IER = READ_PORT_UCHAR(SER_IER(ComPortBase));
-	WRITE_PORT_UCHAR(SER_IER(ComPortBase), IER | SR_IER_THR_EMPTY);
 }
 
 BOOLEAN STDCALL