Subject: Re: More Device Properties
To: None <email@example.com>
From: Chris G. Demetriou <firstname.lastname@example.org>
Date: 02/14/2001 11:57:16
> Right. See the accompanying patch.
People shouldn't have to even look at the patch to get a clear
understanding of how the idea works.
Unfortunately, I don't have time to spend reading anything other than
'final' patches. I probably don't even have time for that.
> I struggled with this a bit and decided that using `struct device *' in
> some contexts and `struct devproplist *' in others broke orthogonality,
> encapsulation, and consistency.
I don't see why you'd use 'struct device' in any when dealing with the
It would probably be nice to have a conveninence macro to give you the
properties for a given device, which could simply be a macro at this
> The interfaces could all be changed to operate on device property lists,
> but that doesn't seem as clean an implementation to me.
It's certainly better than faking up a bogus 'struct device,' to my
> That would also
> preclude any possibility of implemnting as anything other than a linked
> list in future, such as database table.
Why would it do that?
I think if you do all of the above, you;
(1) end up with an interface that nicely encapsulates device
properties as separate objects,
(2) you don't end up with gross hacks like faking up a struct device,
(3) it doesn't actually hurt your ability to implement things in a
database at some point in the future,
(4) if you find that you _really need_ the properties container to be
a 'struct device' for some reason, you could in fact do that with
> I'm not sure I like the extra copying that get_devprop() requires,
> either, but I'm kinda ambivalent about that.
> It simplifies memory management since you don't need to worry about
> having dangling references to data that's been freed.
Yeah -- I think it's reasonable. There's probably no better solution.
> Anyway, if you plan to replace the aux information with properties, it is
> best to encode them as separate proerties rather than a fixed `aux'
Yeah, that's fairly obvious.
The case i'm most worried about is where you're passing down e.g. a
'bus chipset' handle of some sort, and want to make sure it doesn't
accidentally get nuked while you're still using it...