Re: [PATCH] Paravirt framebuffer frontend kernel support [1/5]

[Markus Armbruster <armbru@redhat.com>]

Ewan Mellor <ewan@xensource.com> writes:

> On Thu, Nov 02, 2006 at 11:10:12AM +0100, Markus Armbruster wrote:
>
>> I'm now looking into a conversion to xenbus_driver API.  I started
>> with copying some voodoo from blkfront.c.  My
>> xenbus_register_frontend() succeeds.  Stupid question: what triggers
>> running of the probe function?  Because mine doesn't.
>
> Either the watch firing when the correct entries in the store are written (for
> hotplugging) or it probes those paths at startup.
>
> xenbus/xenbus_probe.c:
>
> frontend_changed ->
> dev_changed ->
> xenbus_probe_node ->
> device_register
>
> or
>
> xenbus_probe_init ->
> xenbus_probe ->
> xenbus_probe_devices ->
> xenbus_probe_device_type ->
> bus->probe ->
> xenbus_probe_frontend ->
> xenbus_probe_node ->
> device_register
>
> The device_register causes a the specific frontend device to be registered,
> which triggers the probe.

Err, I still don't get it.  What exactly makes the guest run the
frontend's probe?  I figure you're trying to tell me that it runs when
a certain xenstore entry is present at startup, or when it gets
created later.  Corrrect?  Which entry exactly?  I tried a few (more
voodoo), but no luck.