[Qemu-devel] [PATCH] serial: fix DLL writes

[Paolo Bonzini]

Commit 0147883450fe84bb8de2d4a58381881f4262ce9b tries to handle
word-sized writes to DLL/DLH, but due to a typo,
this patch is causing tracebacks in all Linux kernels running the PXA
serial driver, due to an unexpected DLL register value. Here is the
surrounding code from drivers/tty/serial/pxa.c:

        serial_out(up, UART_DLL, quot & 0xff);          /* LS of divisor */

        /*
         * work around Errata #75 according to Intel(R) PXA27x
         * Processor Family Specification Update (Nov 2005)
         */
        dll = serial_in(up, UART_DLL);
        WARN_ON(dll != (quot & 0xff));  // <-- warning

Reported-by: Guenter Roeck <address@hidden>
Tested-by: Guenter Roeck <address@hidden>
Fixes: 0147883450fe84bb8de2d4a58381881f4262ce9b
Signed-off-by: Paolo Bonzini <address@hidden>
---
 hw/char/serial.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/char/serial.c b/hw/char/serial.c
index 251f40fdac..02463e3388 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -345,9 +345,9 @@ static void serial_ioport_write(void *opaque, hwaddr addr, 
uint64_t val,
     default:
     case 0:
         if (s->lcr & UART_LCR_DLAB) {
-            if (size == 2) {
+            if (size == 1) {
                 s->divider = (s->divider & 0xff00) | val;
-            } else if (size == 4) {
+            } else {
                 s->divider = val;
             }
             serial_update_parameters(s);
-- 
2.17.1