Re: [RFC PATCH 0/9] dt: dependencies (for deterministic driver initialization order based on the DT)

From: Alexander Holler
Date: Tue Aug 26 2014 - 06:19:08 EST

Am 26.08.2014 10:51, schrieb Grant Likely:

Getting the dependency tree I think is only half the problem. The other
have is how to get the driver model to actually order probing using that
list. That problem is hard because the order drivers are probed is
currently determined by the interaction of driver link order, driver
initcall level, and device registration order. The first devices are
> registered at an early initcall, before their drivers, and therefore
> bind order is primarily determined by initcall level and driver link
> order. However, later devices (ie. i2c clients) are registered by the
> bus driver (ie. again, i2c) and probe order may be primarily link order
> (if the driver is not yet registered) or registration order (if the
> driver was registered before the parent bus).

Using my patches, the problem which still exists is how to handle devices (not drivers). I've build the patches based on the assumption that device-handling happens automatically. Unfortunately that isn't really true and device-handling looks awkward. Some drivers build them themself, some require that a device already exists and some require that a device doesn't already exist.

But I haven't looked in deep at that. I'm sure that can be fixed by fixing drivers which do things differently than they should (maybe because they needed to do such for dirty workarounds because no order was guaranteed, which wouldn't be true anymore).

Anyway, I've not looked further into that problem (with devices, not drivers) as it already seems quiet impossible to get the other necessary stuff into the kernel in a reasonable time (before 32bit-HW which does use DT will not be available anymore).


Alexander Holler
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at