From: Gerd Hoffmann There is a bug in the UART_BUG_TXEN test: It gives false positives in case the UART_IER_THRI bit is set. Fixed by explicitly clearing the UART_IER register first. It may trigger with an active serial console as serial console writes set the UART_IER_THRI bit. Signed-off-by: Gerd Hoffmann Cc: Russell King Signed-off-by: Andrew Morton --- drivers/serial/8250.c | 1 + 1 files changed, 1 insertion(+) diff -puN drivers/serial/8250.c~serial-fix-uart_bug_txen-test drivers/serial/8250.c --- devel/drivers/serial/8250.c~serial-fix-uart_bug_txen-test 2006-05-11 15:18:10.000000000 -0700 +++ devel-akpm/drivers/serial/8250.c 2006-05-11 15:18:10.000000000 -0700 @@ -1646,6 +1646,7 @@ static int serial8250_startup(struct uar * Do a quick test to see if we receive an * interrupt when we enable the TX irq. */ + serial_outp(up, UART_IER, 0); serial_outp(up, UART_IER, UART_IER_THRI); lsr = serial_in(up, UART_LSR); iir = serial_in(up, UART_IIR); _