Re: PNP: dynamic pnp resources

Bjorn Helgaas
2008-03-13T15:14:28Z

On Thursday 13 March 2008 06:04:08 am Thomas Renninger wrote:
> On Wed, 2008-03-12 at 13:45 -0400, Len Brown wrote:
> > On Wednesday 12 March 2008, Dave Jones wrote:
> ...
> > Thomas worked on a patch to make resource allocation dynamic and do away
> > with these limits. Unfortunately it was rather large and it wasn't in
> > time for the 2.6.25-rc1 window.
>
> I had the problem that I could not test on isa systems.
> Rene Herman helped here a lot.
> There are still open issues, last state was (comment from Rene):
> ------------------------
> No. Please note we're talking about ISAPnP, not PnPBIOS. No BIOS
> involved at all.
>
> Driver (sound/isa/cs423x/cs4236.c) furthermore does not use anything but
> the PnP layer itself. Start at snd_cs423x_pnpc_detect, which is the
> pnp .probe() method.
>
> I'll look into providing a more extensive answer and/or test whatever
> comes in later.
> -------------------------
> I can also look at this, any hints until then are appreciated.
>
> I also expect Bjorn was bound to other bugs and pushing things in a rush
> is not good thing anyway.
> At the end I asked for a macro problem I only had a rather ugly
> solution, didn't get an answer (IIRC I also added a compile bug in my
> suggestions) and things got stuck...
>
> Do you want me to rework the patches, lay out where I see problems and
> give it another try to get this into -mm?

I'm sorry that I haven't responded to this. I have some reservations,
but I wanted to try out some alternate ideas before just being a nay-
sayer because usually my grand ideas turn out to have fatal flaws.

My current grand but untested idea is that struct pnp_resource_table
is too exposed and should be better abstracted, even inside the PNP
subsystem. Since PNP is supposed to be a way to discover platform
devices, I'm looking at the platform device interfaces for ideas.

Whatever we do, I think it has to be done incrementally to make it
reviewable and bisectable.

Bjorn