[PATCH 2.6.18-rc5] PCI: sort device lists breadth-first

From: Ragnar Kjørstad
Date: Sat Sep 09 2006 - 10:34:53 EST


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> Solution:
>
> The solution can come in multiple steps.
>
> Suggested fix #1: kernel
> Patch below sorts the two device lists into breadth-first ordering to
> maintain compatibility with 2.4 kernels. It also overloads the
> 'pci=nosort' option to disable the breadth-first sort (and on i386 it
> continues to disable the pcibios_find_device sort as well).

As far as I understand it's difficult to argue that sorting the devices
one way is more "correct" than the other, so your argument is basically:
1) Compability with 2.4
2) Consistency with BIOS and external labels.

Both are important, but the problem is
1) Compability with 2.4 means breaking compability with previous
2.6 kernels. And 2.6 has been out long enough that it's more
important than 2.4.
2) There is also hardware where the 2.6 behaviour is consistent with
BIOS and external labels where 2.4 is not.

An _option_ to enable 2.4 compatible device ordering on the other hand
would have just advantages, no disadvantages.


--
Ragnar Kjørstad
Software Engineer
Scali - http://www.scali.com
Scaling the Linux Datacenter
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