who invokes device's probe function?

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who invokes device's probe function?

Anton Korenyushkin
Hello,

I've written simple back/front end drivers. They initialize their xenbus
drivers. But probe functions are never executed. I heared that xend does this
stuff. How can i make xend probe my driver?

--
Best regards,
Anton Korenyushkin
mailto:[hidden email]

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Re: who invokes device's probe function?

Ewan Mellor
On Thu, Oct 13, 2005 at 06:20:19PM +0400, Anton Korenyushkin wrote:

> Hello,
>
> I've written simple back/front end drivers. They initialize their xenbus
> drivers. But probe functions are never executed. I heared that xend does this
> stuff. How can i make xend probe my driver?

Inside drivers/xen/xenbus/xenbus_probe.c there are watches registered on the
device and backend paths in the store.  These are implicitly rooted to match
the bit in the store corresponding to the domain, so these watches should be
on /local/domain/<domid>/device and /local/domain/<domid>/backend.  When Xend
writes into these locations, the xenbus driver should check whether the device
has already been configured (inside dev_changed) and if not, will call
xenbus_probe_node which will register a new device corresponding to your
front/backend device, all being well.  It will then create device files, a
side-effect of which will be to probe the front/backend driver itself.

HTH,

Ewan.

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