On Thu, Nov 21, 2013 at 12:18 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
>
> 3. or more generic, treat all pci BAR 32bit prefetechable as normal
> MMIO32 during allocation. aka mmio prefectechable will be used for pci
> bridge that support 64bit mmio pref and leave bridge's 32bit only pref
> bar register blank.
>
> Bjorn, Linus,
> Are you happy with No 3?
I don't think I understand your #3. If there's a 32-bit device behind
the bridge, it will need to be in the low 4G, so you can't use the
64-bit window because it will be out of range. So that wouldn't work.
So you'd need to have a bridge window in the low 32-bit area too if
there are any 32-bit devices behind the bridge.
Also, haven't we tried the "try to allocate 64-bit devices in high
memory" and it has always failed because there are broken devices?
Linus
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