[PATCH] serial.c 2.4.20 - ST16654 xmit data loss

[Ed Vance]

Fixes transmit FIFO overrun that affects ST16654 UART only.
Bug found by William King [[e-mail]]
Symptom: random loss of transmit data, worse at low baud rates.
Cause: on 16654 UART, default transmit FIFO trigger level is 8
       instead of zero, so full FIFO depth is not available 
       when transmit interrupt arrives. Race between UART 
       transmitting last 8 bytes still in TX FIFO and driver 
       writing full FIFO length of new data to TX FIFO.

diff -Naur -X dontdiff.txt linux-2.4.20/drivers/char/serial.c
patched-2.4.20/drivers/char/serial.c
--- linux-2.4.20/drivers/char/serial.c	Thu Nov 28 15:53:12 2002
+++ patched-2.4.20/drivers/char/serial.c	Tue May 27 15:14:58 2003
@@ -306,8 +306,8 @@
 	{ "TI16750", 64, UART_CLEAR_FIFO | UART_USE_FIFO},
 	{ "Startech", 1, 0},	/* usurped by cyclades.c */
 	{ "16C950/954", 128, UART_CLEAR_FIFO | UART_USE_FIFO},
-	{ "ST16654", 64, UART_CLEAR_FIFO | UART_USE_FIFO |
-		  UART_STARTECH }, 
+	{ "ST16654", 64-8, UART_CLEAR_FIFO | UART_USE_FIFO |
+		  UART_STARTECH },	/* ST16654 xmit trigger lvl = 8 */
 	{ "XR16850", 128, UART_CLEAR_FIFO | UART_USE_FIFO |
 		  UART_STARTECH },
 	{ "RSA", 2048, UART_CLEAR_FIFO | UART_USE_FIFO },