Re: INTR-REMAP error with UDD driver

[Per Oberg <pero@wolfram.com>]

> I would like to revive this thread from several months ago:

> https://xenomai.org/pipermail/xenomai/2019-March/040498.html

> The issue is that on some hardware (a specific rack-mount PC with a PICMG
> daughtercard on a backplane containing PCI and PCIe slots) I get an INTR-REMAP
> error when trying to receive legacy (not MSI) interrupts from a custom
> FPGA-based PCI card using a UDD driver. The card did work properly in one out
> of the five PCI slots on that machine, but UDD interrupts did not work in the
> other four slots.

This looks very close to my issue. This was under an experimenting phase of the project, so unfortunately I cannot re-test anything because I don't have the hardware. If I recall correctly the hardware involved where 

PC
---------------
One of these worked, the other did not (sorry, this is all I can remember)
* Advantech ARK-3500, embedded PC [1] (hard to find a  good description)
* Advantech AIMB-585, Motherboard [2] 

This definitely worked
* HP Z620 Workstation 


PCI/PCIe
* PCAN-PCI Express Four Channel, not manufactured any more (Closest is 2 Channel IPEH-003027)

[1] https://advdownload.advantech.com/productfile/PIS/ARK-3500/Product%20-%20Datasheet/ARK-3500_DS(11.16.16)20161116101733.pdf
[2] https://advdownload.advantech.com/productfile/PIS/AIMB-585/Product%20-%20Datasheet/AIMB-585_DS(12.28.17)20171228141058.pdf

> Please review the original thread for more details about the specific error.

> Here are a few more tidbits I have gathered:

> - The UDD driver / userspace code works fine on the other hardware

> - The UDD driver / userspace code works fine in one PCI slot out of five on this
> hardware.

> - With another backplane model, but same processor card, the problem occurs in
> all four of the PCI slots.

> - An almost identical pure-linux UIO version of the driver / userspace code
> works in all the cases I tested, even when the UDD version fails, and even with
> the same xenomai-patched kernel used for UDD testing.

This also fits my memory of the issue I had. 

> In one of the previous posts in this thread a few months ago, Per Öberg
> mentioned experiencing something similar. Based on the information that was
> shared, I tried my code with linux version 4.9.38, but it still failed. This
> prompted me to try other linux / ipipe / xenomai combinations. These are my
> findings:

> Interrupts work:
> xenomai-2.6.5 ipipe-core-3.18.20-x86-7.patch (2016-07-05)
> xenomai-3.0.9+ ipipe-core-3.18.20-x86-7.patch (2016-07-05)
> xenomai-3.0.9+ ipipe-core-4.1.18-x86-9.patch (2017-05-25)

> INTR-REMAP error:
> xenomai-3.0.9+ ipipe-core-4.4.43-x86-6.patch (2017-02-25)
> xenomai-3.0.9+ ipipe-core-4.4.43-x86-7.patch (2017-05-25)
> xenomai-3.0.9+ ipipe-core-4.4.43-x86-8.patch (2017-06-14)
> xenomai-3.1-rc3 ipipe-core-4.4.196-cip38-x86-19.patch (2019-11-04)
> xenomai-3.0.9+ ipipe-core-4.9.38-x86-4.patch (2017-10-03)
> xenomai-3.0.9 ipipe-core-4.14.132-x86-6.patch (2019-07-03)

> The Xenomai 2.6.5 version of course does not use UDD, but uses the old
> pthread_intr_* userspace functions.

> Hopefully this additional information can shed a little light on the matter.

> Thanks in advance for any input you can provide,

> -Jeff Webb

Per Öberg