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

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

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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