M A Young wrote:
> On Tue, 5 May 2009, Randy Dunlap wrote:
>
>> From: Randy Dunlap <[email protected]>
>>
>> When a driver kconfig symbol =m and it selects another symbol,
>> that other symbol will also be =m (unless something else
>> causes it to be =y), so when XEN_BLKDEV_FRONTEND=m and/or
>> XEN_NETDEV_FRONTEND=m, then XEN_XENBUS_FRONTEND=m, but that
>> won't build (build error message below). Changing
>> XEN_XENBUS_FRONTEND from a tristate to a bool makes it be
>> =y (builtin) any time that it is selected, so there is
>> no build error.
>
> That isn't the right solution. The real problem is that something you
> have selected as "y" does depend on XEN_XENBUS_FRONTEND but doesn't
> select it. Switching XEN_XENBUS_FRONTEND from tristate to bool might
> fix your particular compile problem, but it means that the situation
> you would get if you changed your configuration so that
> XEN_BLKDEV_FRONTEND=n and XEN_NETDEV_FRONTEND=n (likewise any other
> options that do select XEN_XENBUS_FRONTEND) would still broken because
> then XEN_XENBUS_FRONTEND won't be selected at all.
>
> If your configuration has XEN_PCI_PASSTHROUGH=y then I posted a patch
> for this very situation a few days ago (and it is now in xen-tip/next,
> though wasn't yet in xen-tip/master when I last checked).
pcifront wasn't meant to go into master yet. I'd be interested in some
testing feedback from next.
These xenbus config options seem to be in a bit of a mess, and it would
be nice if someone could go through and make them sane. I think the
ideal outcome should be:
* the backend and frontend should be independently modular
* they should be independently selectable (in principle we should
allow a backend-only kernel, which I don't think is possible atm)
* rather than having separate configs for frontends and backends,
and a config frontend/backend xenbus, why not make the drivers
depend on their appropriate xenbus, and directly configure them?
Anyone?
J
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