Virtualization - Jan 2013 - [PATCH] virtio_console: Let unconnected rproc device receive data.

From: Sjur Br?ndeland <sjur.brandeland at stericsson.com>

Allow rproc serial ports to receive data before the port
is connected.

Rproc serial ports usually talk to very simple remote devices
with no control queue managing open/close events. So we must
let remote devices write to the virtio ring even if the device
is not yet fully initialized.

Signed-off-by: Sjur Br?ndeland <sjur.brandeland at stericsson.com>
---

This patch is intended for v3.9.

Thanks,
Sjur

 drivers/char/virtio_console.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index ee4dbea..c17b053 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1763,8 +1763,11 @@ static void in_intr(struct virtqueue *vq)
 	 * tty is spawned) and the host sends out data to console
 	 * ports.  For generic serial ports, the host won't
 	 * (shouldn't) send data till the guest is connected.
+	 * However a remote device might send data before the port is
+	 * connected. So don't remove data from a rproc_serial device.
 	 */
-	if (!port->guest_connected)
+
+	if (!port->guest_connected &&
!is_rproc_serial(port->portdev->vdev))
 		discard_port_data(port);
 
 	spin_unlock_irqrestore(&port->inbuf_lock, flags);
-- 
1.7.5.4

sjur.brandeland at stericsson.com writes:
> From: Sjur Br?ndeland <sjur.brandeland at stericsson.com>
>
> Allow rproc serial ports to receive data before the port
> is connected.
>
> Rproc serial ports usually talk to very simple remote devices
> with no control queue managing open/close events. So we must
> let remote devices write to the virtio ring even if the device
> is not yet fully initialized.
>
> Signed-off-by: Sjur Br?ndeland <sjur.brandeland at stericsson.com>
Thanks, applied.

Cheers,
Rusty.

On (Thu) 17 Jan 2013 [13:22:42], sjur.brandeland at stericsson.com
wrote:
> From: Sjur Br?ndeland <sjur.brandeland at stericsson.com>
> 
> Allow rproc serial ports to receive data before the port
> is connected.
> 
> Rproc serial ports usually talk to very simple remote devices
> with no control queue managing open/close events. So we must
> let remote devices write to the virtio ring even if the device
> is not yet fully initialized.
> 
> Signed-off-by: Sjur Br?ndeland <sjur.brandeland at stericsson.com>
> ---
> 
> This patch is intended for v3.9.
> 
> Thanks,
> Sjur
> 
>  drivers/char/virtio_console.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
> index ee4dbea..c17b053 100644
> --- a/drivers/char/virtio_console.c
> +++ b/drivers/char/virtio_console.c
> @@ -1763,8 +1763,11 @@ static void in_intr(struct virtqueue *vq)
>  	 * tty is spawned) and the host sends out data to console
>  	 * ports.  For generic serial ports, the host won't
>  	 * (shouldn't) send data till the guest is connected.
> +	 * However a remote device might send data before the port is
> +	 * connected. So don't remove data from a rproc_serial device.
>  	 */
> -	if (!port->guest_connected)
> +
> +	if (!port->guest_connected &&
!is_rproc_serial(port->portdev->vdev))
>  		discard_port_data(port);
How about setting port->guest_connected = true in the init routines
instead?  Keeps this code path cleaner.

That's what console ports do as well, in init_port_console().

		Amit