Intel I350 mini-PCIe card (igb) on Mirabox (mvebu / Armada 370)

Willy Tarreau w at
Tue Apr 8 10:53:24 PDT 2014

Hi Jason,

On Tue, Apr 08, 2014 at 11:14:17AM -0600, Jason Gunthorpe wrote:
> The mbus hardware requires a power of two size, if a non-power
> of two is passed in to the low level routines they configure the
> register in a way that results in undefined behaviour.
> - WARN_ON to make this invalid usage really obvious
> - Round down to the nearest power of two so we only stuff a valid
>   size into the HW

So if I understand it right, for example when my first NIC registers
e0000000-e02fffff, then we'll truncate it down to e0000000-e01fffff,
won't that cause any issue, for example if the NIC needs to access
data beyond that limit ?

BTW I can try your patch with the myricom NIC which started to work
when rounding up, I'll quickly see if that fixes the issue as well,
but I'm now a little bit confused.


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