Re: [PATCH 2/2] PCI: Only enable realloc auto when root bus has 64bit mmio

[Bjorn Helgaas]

On Mon, Dec 9, 2013 at 1:10 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> On Mon, Dec 9, 2013 at 11:42 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
>> That doesn't answer my question at all.
>>
>> I understand that this change makes it so Joseph doesn't have to use
>> "pci=realloc=off".  But why should auto-reallocation be limited to
>> buses that have resources above 4GB?  That doesn't make any sense.
>>
>> We should fix the reallocation code so it can deal with this case.  If
>> there's not enough space for everything, obviously we have to leave
>> something unassigned.  A ROM BAR is a good candidate for leaving
>> unassigned, because most of the time we can get along without it.
>
> Yes, that is ideal and not that simple.
> but that would be hard to backport to old kernels.

Yes, I agree.  I didn't say it would be simple.  The quick fix would
be easy for now, but adding nonsensical code makes our lives harder
long into the future.

Bjorn
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