x86: realmode: fix serial_init()
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@vmware.com>
Message-Id: <20200701193045.31247-1-namit@vmware.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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 @@
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
