From patchwork Mon Feb 4 12:50:50 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [4/4] virtio: console: add flow control Date: Mon, 04 Feb 2013 02:50:50 -0000 From: Amit Shah X-Patchwork-Id: 217901 Message-Id: To: Anthony Liguori Cc: Amit Shah , qemu list The virtio-serial-bus already has the logic to make flow control work properly. Hook into the char layer's new ability to signal a backend is writable again. Signed-off-by: Amit Shah --- hw/virtio-console.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/virtio-console.c b/hw/virtio-console.c index 46072a0..0cf6072 100644 --- a/hw/virtio-console.c +++ b/hw/virtio-console.c @@ -20,6 +20,18 @@ typedef struct VirtConsole { CharDriverState *chr; } VirtConsole; +/* + * Callback function that's called from chardevs when backend becomes + * writable. + */ +static gboolean chr_write_unblocked(GIOChannel *chan, GIOCondition cond, + void *opaque) +{ + VirtConsole *vcon = opaque; + + virtio_serial_throttle_port(&vcon->port, false); + return false; +} /* Callback function that's called when the guest sends us data */ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len) @@ -48,6 +60,7 @@ static ssize_t flush_buf(VirtIOSerialPort *port, const uint8_t *buf, size_t len) * do_flush_queued_data(). */ ret = 0; + qemu_chr_fe_add_watch(vcon->chr, G_IO_OUT, chr_write_unblocked, vcon); } return ret; }