Re: PCI/USB Vendor and model from database

[Greg KH <greg@kroah.com>]

On Wed, Dec 29, 2010 at 05:08:56PM +0100, José Félix Ontañón wrote:
> El día 29 de diciembre de 2010 01:18, Scott James Remnant
> <scott@netsplit.com> escribió:
> > 2010/12/28 Lennart Poettering <lennart@poettering.net>:
> >> On Tue, 28.12.10 14:14, José Félix Ontañón (felixonta@gmail.com) wrote:
> >>
> >>> Hi, everybody!
> >>>
> >>> Maybe this is kinda silly question but, I wonder why isn't
> >>> "ID_VENDOR_FROM_DATABASE / ID_MODEL_FROM_DATABASE"-like properties
> >>> imported by default using the pretty /lib/udev/usb-db and
> >>> /lib/udev/pci-db commands for every founded pci/usb device?
> >>>
> >>> I mean, by adding this simple rules:
> >>>
> >>> SUBSYSTEMS="usb", IMPORT{program}="usb-db %p"
> >>> SUBSYSTEMS="pci", IMPORT{program}="pci-db %p"
> >>>
> >>> I think this properties are very useful for apps that discover
> >>> hardware through udev, so they will not have to reinvent the wheel by
> >>> finding vendor/product names by themselves. Don't you think?
> >>
> >> The database lookup is a linear search. As long as we invoke it only for
> >> a small subset of devices that doesn't really matter much. But if we
> >> start to look it up for every device we should probably spend the time
> >> to improve the db lookup first.
> >>
> >> It's simply a question of efficiency.
> >>
> > One thing that might be interesting is if we could do the lookup at
> > the point of query, then store the answer back in the db for others to
> > use later.
> >
> > That way we're efficient if nobody cares, and lose that efficiency
> > when they do (but only for the devices they query), and subsequently
> > efficient because the answer is cached.
> >
> > This veers a bit dangerously towards having apps that link with
> > libudev process rules though?
> >
> > Scott
> >
> 
> First thing coming to my mind: there's not enough pci/usb devices
> present on the system for increasing the computational cost
> significantly.

How can you say that?  I see systems with thousands of PCI devices on it
as being very common in some areas.

> I think it's quite comfortable, for me as desktop app coder, to
> delegate on udev the vendor/model name querying, more if we think udev
> provides the cool pci-db and usb-db commands.

Again, what's wrong with using libpci directly for this?  That's what it
is there for.

thanks,

greg k-h