[RFC] acpi _CRS analyzation for PCMCIA resource management

Russell King rmk+pcmcia at arm.linux.org.uk
Sun Mar 28 16:11:18 BST 2004

On Sun, Mar 28, 2004 at 03:49:54PM +0200, Dominik Brodowski wrote:
> One of the biggest challanges of 16-bit PCMCIA is to determine which 
> resources (IO-ports and IO-memory) are available for PCMCIA cards. And as
> Russell and others explained to me lately, even on so-called 
> "legacy-free PCs", not all such resources are detectable, so whatever 
> mentioned in /proc/ioports and /proc/iomem is only a guess...

I think this is something which should not be PCMCIA-centric.  Whenever
we want to allocate a resource, whether it be PCMCIA or some other
subsystem, we need this information available to us.

I therefore think it should be manipulating the kernels central resource
manager rather than trying to produce some new separate database.

Now, the way allocate_resource() works is that it will only allocate
resources from the parent resource provided the region is completely
unused.  This means that if you allocate a non-busy resource, it
effectively marks it "produced" but not "consumed", and as such is
not available for allocation by PCMCIA or other subsystems.

Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core

More information about the linux-pcmcia mailing list