serial: poll the serial console with G_IO_HUP

On FreeBSD polling a master pty while the other end is not connected
with G_IO_OUT only results in an endless wait. This is different from
the Linux behaviour, that returns immediately. In order to demonstrate
this, I have the following example code:

http://xenbits.xen.org/people/royger/test_poll.c

When executed on Linux:

$ ./test_poll
In callback

On FreeBSD instead, the callback never gets called:

$ ./test_poll

So, in order to workaround this, poll the source with G_IO_HUP (which
makes the code behave the same way on both Linux and FreeBSD).

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: xen-devel@lists.xenproject.org
[Add hw/char/cadence_uart.c too. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/monitor.c b/monitor.c
index 799131bd01..5bc70a642d 100644
--- a/monitor.c
+++ b/monitor.c
@@ -321,7 +321,7 @@ static void monitor_flush_locked(Monitor *mon)
             mon->outbuf = tmp;
         }
         if (mon->out_watch == 0) {
-            mon->out_watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,
+            mon->out_watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT|G_IO_HUP,
                                                    monitor_unblocked, mon);
         }
     }