Hey,
On Mon, Mar 22, 2010 at 01:08:35PM -0700, Bjorn Helgaas wrote:
> > So, what should we do?
>
> Let's back up a bit. I don't know enough about PCMCIA, and I don't
> see the problem yet. We have the 00:1e.0 bridge leading to bus 04,
> and 04:06.0 is a CardBus bridge. These three windows are the ranges
> positively decoded and forwarded by the 00:1e.0 bridge:
>
> yenta_cardbus 0000:04:06.0: pcmcia: parent PCI bridge I/O window: 0x1000 - 0x1fff
> yenta_cardbus 0000:04:06.0: pcmcia: parent PCI bridge Memory window: 0xd2000000 - 0xd40fffff
> yenta_cardbus 0000:04:06.0: pcmcia: parent PCI bridge Memory window: 0xd0000000 - 0xd1ffffff
>
> But the bridge is in subtractive-decode mode, so it *also* forwards
> anything it sees that is unclaimed by other devices on bus 00, which
> means the 04:06.0 CardBus bridge will also see these ranges:
>
> yenta_cardbus 0000:04:06.0: pcmcia: parent PCI bridge I/O window: 0x0 - 0xcf7
> yenta_cardbus 0000:04:06.0: pcmcia: parent PCI bridge I/O window: 0xd00 - 0xffff
> yenta_cardbus 0000:04:06.0: pcmcia: parent PCI bridge Memory window: 0xa0000 - 0xbffff
> yenta_cardbus 0000:04:06.0: pcmcia: parent PCI bridge Memory window: 0xc0000000 - 0xfebfffff
>
> Why do you care whether these additional ranges are excluded? They
> should be just as usable as the first three.
Quoting rsrc_nonstatic.c:
/* If this is the root bus, the risk of hitting
* some strange system devices which aren't protected
* by either ACPI resource tables or properly requested
* resources is too big. [...]
*/
Or, as Alan put it -- when it came to I/O resources in the 0x100-0x3ff area:
"Which crashes older thinkpads, some ATI chipset systems and
usually anything containing an NE2000 clone in ISA space."
You can still use subtractive-decoded resources, but then you have to add
them to /etc/pcmcia/config.opts and run pcmcia-startup-bridges (or echo the
resource to a sysfs file).
Now, "usecrs" is only used on 2008-or-newer systems where we _hope_ that all
resource "consumers" are accounted for. So the problem might be mitigated.
However, I wouldn't dare to use ioports 0x0-0xff anyways for they usually
are used for onboard legacy devices...
Best,
Dominik
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