Re: introduce device_is_attached()

[David Young <dyoung%pobox.com@localhost>]

On Mon, Apr 16, 2012 at 06:52:28PM +0200, Christoph Egger wrote:
> 
> Hi,
> 
> I want to introduce a new function to sys/devices.h:
> 
> bool device_is_attached(device_t parent, cfdata_t cf);
> 
> The purpose is for bus drivers who wants to attach children
> and ensure that only one instance of it will attach.
> 
> 'parent' is the bus driver and 'cf' is the child device
> as passed to the submatch callback via config_search_loc().
> 
> The return value is true if the child is already attached.
> 
> I implemented a reference usage of it in amdnb_misc.c to ensure
> that amdtemp only attaches once on rescan.

Don't add that function.  Just use a small amdnb_misc softc to track
whether or not the amdtemp is attached or not:

struct amdnb_misc_softc {
        device_t sc_amdtemp;
};

Don't pass a pci_attach_args to amdtemp.  Just pass it the chipset tag
and PCI tag if that is all that it needs.

I'm not sure I fully understand the purpose of amdnb_miscbus.
Are all of the functions that do/will attach at amdnb_miscbus
configuration-space only functions, or are they something else?  Please
explain what amdnb_miscbus is for.

Dave

-- 
David Young
dyoung%pobox.com@localhost    Urbana, IL    (217) 721-9981