Re: [Xen-devel] [Qemu-devel] [PATCH v2 3/3] serial: poll the serial console with G_IO_HUP

[Paolo Bonzini <pbonzini@xxxxxxxxxx>]

Il 30/06/2014 13:00, Roger Pau Monnà ha scritto:
> Do I need to resend this? it's been more than a month without review.
I'll send a pull request for it.

Sorry for the delay.

Paolo

> On 13/06/14 17:35, Roger Pau Monnà wrote:
> > Ping?
> >
> > On 23/05/14 17:57, Roger Pau Monne wrote:
> > > 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
> > > ---
> > > Changes since v1:
> > >  - Fix other users of qemu_chr_fe_add_watch to use G_IO_HUP.
> > > ---
> > >  hw/char/serial.c         |    2 +-
> > >  hw/char/virtio-console.c |    3 ++-
> > >  hw/usb/redirect.c        |    2 +-
> > >  monitor.c                |    2 +-
> > >  4 files changed, 5 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/hw/char/serial.c b/hw/char/serial.c
> > > index f4d167f..2a2c9e5 100644
> > > --- a/hw/char/serial.c
> > > +++ b/hw/char/serial.c
> > > @@ -246,7 +246,7 @@ 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;
> > >          }
> > > diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c
> > > index 6c8be0f..38e290a 100644
> > > --- a/hw/char/virtio-console.c
> > > +++ b/hw/char/virtio-console.c
> > > @@ -69,7 +69,8 @@ static ssize_t flush_buf(VirtIOSerialPort *port,
> > >          if (!k->is_console) {
> > >              virtio_serial_throttle_port(port, true);
> > >              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);
> > >              }
> > >          }
> > > diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
> > > index 287a505..06e757d 100644
> > > --- a/hw/usb/redirect.c
> > > +++ b/hw/usb/redirect.c
> > > @@ -284,7 +284,7 @@ static int usbredir_write(void *priv, uint8_t *data, int 
> > > count)
> > >      r = qemu_chr_fe_write(dev->cs, data, count);
> > >      if (r < count) {
> > >          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);
> > >          }
> > >          if (r < 0) {
> > > diff --git a/monitor.c b/monitor.c
> > > index 593679a..ae1c539 100644
> > > --- a/monitor.c
> > > +++ b/monitor.c
> > > @@ -304,7 +304,7 @@ void monitor_flush(Monitor *mon)
> > >              mon->outbuf = tmp;
> > >          }
> > >          if (mon->watch == 0) {
> > > -            mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,
> > > +            mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT|G_IO_HUP,
> > >                                                 monitor_unblocked, mon);
> > >          }
> > >      }

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