MSI-X vector allocation failure in upstream kernel

MSI-X vector allocation failure in upstream kernel

[Anirban Chakraborty]

Hi All,

I am trying to test qlcnic driver (for 10Gb QLogic network adapter) on a Po=
wer 6 system=20
(IBM P 520, System type 8203) with upstream kernel and I do see that the ke=
rnel is=20
not able to allocate any MSI-X vectors. The driver requests for 4 vectors i=
n pci_enable_msix,
which returns 2. The driver again attempts, this time for 2 vectors but the=
 kernel can't allocate=20
and it returns a value of 0xfffffffd. I upgraded the system FW to 01EL350 (=
from 01EL340)
 just to make sure if MSI-X is enabled in the system. Is there anything tha=
t I am missing?=20

Any pointers will be highly appreciated.


thanks,
Anirban Chakraborty=

Re: MSI-X vector allocation failure in upstream kernel

[Benjamin Herrenschmidt]

On Tue, 2010-10-05 at 10:18 -0700, Anirban Chakraborty wrote:
> Hi All,
> 
> I am trying to test qlcnic driver (for 10Gb QLogic network adapter) on a Power 6 system 
> (IBM P 520, System type 8203) with upstream kernel and I do see that the kernel is 
> not able to allocate any MSI-X vectors. The driver requests for 4 vectors in pci_enable_msix,
> which returns 2. The driver again attempts, this time for 2 vectors but the kernel can't allocate 
> and it returns a value of 0xfffffffd. I upgraded the system FW to 01EL350 (from 01EL340)
>  just to make sure if MSI-X is enabled in the system. Is there anything that I am missing? 
> 
> Any pointers will be highly appreciated.

I think the people who can help you at the moment are on vacation :-)

Can you make sure kernel debug is enabled and you have "debug" on the
kernel command line, and send the full dmesg log of what's going on ?

Hopefully, Michael will be back next week and will be able to have a
look at it.

Cheers,
Ben.

Re: MSI-X vector allocation failure in upstream kernel

[Michael Ellerman]

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On Tue, 2010-10-05 at 10:18 -0700, Anirban Chakraborty wrote:
> Hi All,
> 
> I am trying to test qlcnic driver (for 10Gb QLogic network adapter) on a Power 6 system 
> (IBM P 520, System type 8203) with upstream kernel and I do see that the kernel is 
> not able to allocate any MSI-X vectors. The driver requests for 4 vectors in pci_enable_msix,
> which returns 2.

OK, that's the platform code saying it can only support 2, that seems
low, but it's possible.

>  The driver again attempts, this time for 2 vectors but the kernel can't allocate 
> and it returns a value of 0xfffffffd. 

OK, that's odd. That is -3, which AFAICS we don't return from the linux
code. So it must be coming from firmware? In which case it would be
"parameter error".

> I upgraded the system FW to 01EL350 (from 01EL340) just to make sure
> if MSI-X is enabled in the system.

Is that the latest FW version?

Adding #define DEBUG at the top of arch/powerpc/platforms/pseries/msi.c
will give us lots of useful info.

Or you can enable CONFIG_DYNAMIC_DEBUG, and enable it that way.

cheers

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