[Xen-devel] [PATCH] serial: poll the serial console with G_IO_HUP

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

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 Monnà <roger.pau@xxxxxxxxxx>
Cc: Peter Crosthwaite <peter.crosthwaite@xxxxxxxxxx>
Cc: Michael Tokarev <mjt@xxxxxxxxxx>
Cc: "Andreas FÃrber" <afaerber@xxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
---
 hw/char/serial.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/hw/char/serial.c b/hw/char/serial.c
index 6025592..ab9c40f 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -243,7 +243,7 @@ static gboolean serial_xmit(GIOChannel *chan, GIOCondition 
cond, void *opaque)
         serial_receive1(s, &s->tsr, 1);
     } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) {
         if (s->tsr_retry >= 0 && s->tsr_retry < MAX_XMIT_RETRY &&
-            qemu_chr_fe_add_watch(s->chr, G_IO_OUT, serial_xmit, s) > 0) {
+            qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP, serial_xmit, s) > 
0) {
             s->tsr_retry++;
             return FALSE;
         }
-- 
1.7.7.5 (Apple Git-26)


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