Cardbus broken between 2.6.14-rc2 and -rc3

[Bernhard Kaindl]

On Fri, 31 Mar 2006, Dominik Brodowski wrote:
>
> Does issuing the "pci=assign-busses" boot parameter help?

AFAICS it should, but on machines where there is a chain of two
PCI-PCI bridges above the CardBus bridge, a fix which didn't
make it in time for 2.6.16 may need to be present:

http://www.kernel.org/pub/linux/kernel/people/gregkh/pci/2.6/2.6.16/pci-really-fix-parent-s-subordinate-busnr.patch

For Laptops, that may possibly occur if there is a cardbus
bridge in a docking station.

Since it has been observed that apparently the PCI bus reassignment
which is an integral part of pci=assign-busses may cause problems
if e.g. X11 configs target specific PCI bus numbers, pci=assign-busses
and since it still causes some hangs on  some machines (also reported
here) - a possible cause for this may be that ACPI may contain
references to PCI bus numbers - it does not appear to be the
best possible solution.

The development of a fix which does not appear to have such
drawbacks - and should be enabled always in the future - can
be found there:

http://bugzilla.kernel.org/show_bug.cgi?id=2944#c30

I'll add linux-acpi to the Cc of this bug now, so the list
can be kept up-to-date with updates to this bug.

Bernhard