ioports 0x100-0x3af and iomem 0xd000-0xdffff, 0xa0000000-0xa0ffffff -- safe to use on x86 for pcmcia?

Dominik Brodowski linux at
Sat Nov 28 11:48:19 EST 2009


On Wed, Nov 25, 2009 at 08:56:50PM +0900, Komuro wrote:
> > Do you think it would be safe to enable these areas by (kernel) default on
> > x86? Of course, other entries in /proc/io{mem,ports} would be honoured, there
> > would be a boot option to disable this feature, and some tests are run on the
> > iomem and ioport resource areas.
> The problem you have is that you change the ordering.
> If you load the ne2k ISA driver before pcmcia (as occurs now because of
> it being done from user space) the resources get claimed first. If you do
> it the other way around and test then merely reading an I/O register
> mapped to an NE2K or most NE2K clones crashes the machine.

... and even adding a late_initcall() has its problems.

> Are there any modern systems where the PCI based autoconfig is
> insufficient, or is this just ancient stuff  ?

I'm not familiar with embedded stuff, but usually PCI-based autoconfig
should be sufficient nowadays. Therefore, the only workable way seems to be
an optional module parameter


or something like that. Thanks for the input!


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