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

[Matthew Minter]

This is just a guess but perhaps the best we could do would be to round up but also add logic to fail completely if adding a PCI device would cause a window to overlap?

 This would mean situations will be fixed where we can without design changes and situations that cannot be fixed will fail with clear errors?

On 8 Apr 2014, at 20:21, Jason Gunthorpe <jgunthorpe at obsidianresearch.com> wrote:

> On Tue, Apr 08, 2014 at 09:15:14PM +0200, Willy Tarreau wrote:
> 
>> OK that's what I understood, but I mean why rounding down instead of up
>> in order to correctly cover the window the device expects ? And we all
>> found that rounding up fixed our respective devices (3 igb NICs, one
>> myri10ge NIC, one SATA controller I believe).
>> 
>> By rounding up you'd have had 1ffffff instead, which at least covers the
>> window the device expects.
> 
> It is also an error to configure the mbus to have overlaping windows
> and the code checks for overlaps with the base/size given. If we round
> up then it might create an overlap.
> 
> You guys were OK with the round up in the PCI code only because your
> systems have a single used PEX so the rounding didn't create an
> overlaping situation..
> 
> The generic code should either round down, or compeltely bail, as
> Thomas suggested.
> 
> Fundementally we shouldn't get to the WARN_ON, so what happens after
> is just an attempt to salvage something from the situation.
> 
> Jason

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