Re: [PATCH] drivercore: Add driver probe deferral mechanism

From: Greg KH
Date: Tue Jul 05 2011 - 13:30:32 EST


On Tue, Jul 05, 2011 at 11:17:46AM -0600, Grant Likely wrote:
> On Tue, Jul 5, 2011 at 10:36 AM, Greg KH <gregkh@xxxxxxx> wrote:
> > On Tue, Jul 05, 2011 at 10:28:37AM -0600, Grant Likely wrote:
> >> On Tue, Jul 5, 2011 at 10:11 AM, Kay Sievers <kay.sievers@xxxxxxxx> wrote:
> >> > On Tue, Jul 5, 2011 at 17:50, Greg KH <gregkh@xxxxxxx> wrote:
> >> >
> >> >> I wonder if doing this all from a workqueue in the first place is going
> >> >> to cause problems as probe isn't normally done this way at all.
> >> >
> >> > Yeah, I would expect unforeseen problems with the async thread too.
> >> > It's probably all solvable, but it sounds troublesome to find out if
> >> > things go wrong.
> >> >
> >> > We have sync hooks (BUS_NOTIFY_*) where any kind of code can subscribe
> >> > to when devices get added or get bound to a driver. Can't the code
> >> > that relies on later hookups to already existing devices/bindings not
> >> > just plug into that?
> >>
> >> I tried that.  It resulted in a lot of complexity that each driver
> >> needs to implement correctly which is why I started looking for a
> >> different way to go about it.
> >
> > No, the bus that wants this just has to do it, not the drivers
> > themselves, right?
>
> It's not about the bus_type, and there is nothing that the bus can do
> to solve this problem because it the dependencies are completely
> orthogonal to the bus. ie. what does an i2c bus know about the audio
> path to a codec? The problem must be solved at the driver scope.

Ok, let's look at your next implementation and see how it goes.
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