Re: Exposing device ids and driver names

[Greg KH <greg@kroah.com>]

On Thu, Oct 01, 2009 at 01:01:50PM -0400, Nathaniel McCallum wrote:
> On 10/01/2009 12:42 PM, Greg KH wrote:
> > On Thu, Oct 01, 2009 at 12:40:05PM -0400, Nathaniel McCallum wrote:
> >> Please CC me on any responses as I'm not subscribed to lkml.
> >>
> >> I have the aim at creating two tools helpful to linux.  The first tool
> >> is a driver regression test of sorts.  I want to be able to create
> >> essentially a time line of hardware support as they appear in distros.
> >> The second tool, related to the first, is a program which runs on
> >> Windows and scans for a user's hardware and tells them which distro will
> >> best support their hardware.
> >
> > That's going to be interesting, as all distros pretty much use the same
> > kernel, it will just depend on who is "newer" at the moment, right?
> 
> Mostly yes.  I intend to also trace id diffs against mainline to see if 
> distros have picked up patches that are not upstream.

That should be easier to do by just looking at the diff from mainline to
their kernel.  All distros should be providing this already so it
shouldn't be that hard to run a static code analyzer on it if needed.

> >> I already have a working prototype of these two tools.  It currently
> >> uses the data exported by modinfo.  This however does not provide
> >> transparency for drivers compiled into the kernel.
> >
> > Most distros don't build drivers into the kernel, so you should be fine
> > with what you have today, right?  Or have you run into problems with
> > this?
> 
> I've run into specific problems.  This is obviously the case on 
> specialized distros (which I *do* want to measure).  However, even a 
> quick diff on configs will show differences on major distros with some 
> devices being compiled into the kernel.  It is also often true that ACPI 
> devices are built into the kernel.

Yes, and look at the Moblin builds, we put lots of stuff into the kernel
directly for speed at boot issues.

> > Why not just use the baseline kernel as a model for this.  Do a 'make
> > allmodconfig' and then extract the data and publish it that way.  No
> > kernel changes are needed, and then any distro can be easily matched up
> > by this based on what they are using.  That will save you time in
> > downloading zillions of distro releases, and provide a nice easy way to
> > show what the kernel.org releases support.
> 
> Unfortunately, I would not be able to track changes to the kernel in 
> this model.  Since this is one of my explicit goals (to make sure that 
> distro kernel changes get upstream), I think a non-invasive kernel 
> modification would be worth the effort.

But this was an invasive modification, it added space to the kernel
images for no real benifit other than for your tracking tools.  That's
not going to fly unless you can find another good use for the change.

thanks,

greg k-h