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>
This commit is contained in:
Roger Pau Monne 2014-05-23 17:57:49 +02:00 committed by Paolo Bonzini
parent 9328cfd2fe
commit e02bc6de30
5 changed files with 7 additions and 5 deletions

View File

@ -306,7 +306,8 @@ static gboolean cadence_uart_xmit(GIOChannel *chan, GIOCondition cond,
memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count); memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_count);
if (s->tx_count) { if (s->tx_count) {
int r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT, cadence_uart_xmit, s); int r = qemu_chr_fe_add_watch(s->chr, G_IO_OUT|G_IO_HUP,
cadence_uart_xmit, s);
assert(r); assert(r);
} }

View File

@ -246,7 +246,7 @@ static gboolean serial_xmit(GIOChannel *chan, GIOCondition cond, void *opaque)
serial_receive1(s, &s->tsr, 1); serial_receive1(s, &s->tsr, 1);
} else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) { } else if (qemu_chr_fe_write(s->chr, &s->tsr, 1) != 1) {
if (s->tsr_retry >= 0 && s->tsr_retry < MAX_XMIT_RETRY && 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++; s->tsr_retry++;
return FALSE; return FALSE;
} }

View File

@ -70,7 +70,8 @@ static ssize_t flush_buf(VirtIOSerialPort *port,
if (!k->is_console) { if (!k->is_console) {
virtio_serial_throttle_port(port, true); virtio_serial_throttle_port(port, true);
if (!vcon->watch) { if (!vcon->watch) {
vcon->watch = qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT, vcon->watch = qemu_chr_fe_add_watch(vcon->chr,
G_IO_OUT|G_IO_HUP,
chr_write_unblocked, vcon); chr_write_unblocked, vcon);
} }
} }

View File

@ -290,7 +290,7 @@ static int usbredir_write(void *priv, uint8_t *data, int count)
r = qemu_chr_fe_write(dev->cs, data, count); r = qemu_chr_fe_write(dev->cs, data, count);
if (r < count) { if (r < count) {
if (!dev->watch) { if (!dev->watch) {
dev->watch = qemu_chr_fe_add_watch(dev->cs, G_IO_OUT, dev->watch = qemu_chr_fe_add_watch(dev->cs, G_IO_OUT|G_IO_HUP,
usbredir_write_unblocked, dev); usbredir_write_unblocked, dev);
} }
if (r < 0) { if (r < 0) {

View File

@ -321,7 +321,7 @@ static void monitor_flush_locked(Monitor *mon)
mon->outbuf = tmp; mon->outbuf = tmp;
} }
if (mon->out_watch == 0) { 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); monitor_unblocked, mon);
} }
} }