In some setups serial output from the real-mode tests is corrupted. I do not know the serial port initialization code well, but the protected mode initialization code is different than the real-mode code. Using the protected mode serial port initialization fixes the problem. Keeping the tradition of code duplication between real-mode and protected mode, this patch copies the missing initialization into real-mode serial port initialization. Signed-off-by: Nadav Amit <namit@xxxxxxxxxx> --- x86/realmode.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/x86/realmode.c b/x86/realmode.c index 90ecd13..7c2d776 100644 --- a/x86/realmode.c +++ b/x86/realmode.c @@ -77,6 +77,15 @@ static void serial_init(void) lcr = inb(serial_iobase + 0x03); lcr &= ~0x80; outb(lcr, serial_iobase + 0x03); + + /* IER: disable interrupts */ + outb(0x00, serial_iobase + 0x01); + /* LCR: 8 bits, no parity, one stop bit */ + outb(0x03, serial_iobase + 0x03); + /* FCR: disable FIFO queues */ + outb(0x00, serial_iobase + 0x02); + /* MCR: RTS, DTR on */ + outb(0x03, serial_iobase + 0x04); } #endif -- 2.17.1
