kern/99979: Get Ready for Kernel Module in C++

mag at mag at
Tue Jul 11 19:24:54 UTC 2006

John Baldwin wrote:

> On Tuesday 11 July 2006 12:33, M. Warner Losh wrote:
>> In message: <200607111115.59844.jhb at>
>>             John Baldwin <jhb at> writes:
>> : and OS X both of which I've written a PCI driver for) we require device 
>> : driver writers to go through a lot more hoops to do certain things like 
>> : allocate resources.  At the very least there is much that can be improved 
> in 
>> : our driver model.
>> bus_alloc_resources goes a long ways in this respect.
> Yes, but in OS X I didn't even have to do that.  All I had to do was ask it to 
> map a BAR if I wanted to use it.  It already "allocated" all the resources 
> regardless.  Windows was the same way (though a bit weirder, you get a 
> message that lists all your resources and you have to map them if you want to 
> use them).
> -- 
> John Baldwin

Do you mean that the kernel pre-allocate resources for all devices whether
a device has been attached by a device driver?
Does BIOS do the same thing before OS boots?

                                                From Beijing, China

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