------- Comment From [email protected] 2020-02-19 02:53 EDT-------
Some additional comments about the impact of the patches. They only impact
powerpc and more specifically the powernv platform. Opencapi devices are only
supported on the powernv platform, and require a Power9 processor.
The first 5 patches (powerpc/powernv/pci-ioda) impact the opencapi PCI devices,
and to a much lesser extent the nvlink (GPU) devices.
Patch 05dd7da76986 ("powerpc/powernv/ioda: Fix ref count for devices with their
own PE") technically impacts nvlink (GPUs) PCI devices, but I'm only replacing
a refcounting leak by a (oh so slightly) less ugly leak.
Patch 80f1ff83fa11("powerpc/powernv/ioda: Protect PE list") is for both nvlink
and opencapi, but it looks pretty safe. nvlink devices are discovered at boot
and never go away. Opencapi devices, with that series, can now come and go,
that's why I'm adding the extra lock protection.
The 3 other patches for powerpc/powernv/pci-ioda really impact opencapi PCI
devices only.
The second part of the series is for the powernv PCI hotplug driver
(pnv-php) but there's little there other than adding the new opencapi
slots. For existing PCI slots, it's mostly cosmetics.
Finally, the last patch is to add a dependency on the PCI hotplug
framework for the ocxl driver. Ocxl is the opencapi driver. As
mentioned above, it is only used of Power9 and it's the driver I'm
maintaining.
I hope it clarifies things. I do believe the impact is fairly limited
outside of opencapi device support and I'm trying pretty hard to make
that work.
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https://bugs.launchpad.net/bugs/1862121
Title:
[20.04] Allow to reset an opencapi adapter
Status in The Ubuntu-power-systems project:
Triaged
Status in linux package in Ubuntu:
New
Bug description:
== Comment: #0 - Frederic Barrat <[email protected]> - 2020-01-27
10:56:49 ==
---Problem Description---
We've added code in firmware to allow to reset an opencapi adapter on a
powerpc system, and retrain the opencapi link.
On linux, resetting the opencapi link is re-using the existing PCI hotplug
framework, but there's a bit of enablement code missing and we'd like to add it
to Ubuntu 20.04 since it's a LTS release.
Contact Information = [email protected]
---Additional Hardware Info---
opencapi adapter needed
---uname output---
Linux wsp02 5.3.0-26-generic #28-Ubuntu SMP Wed Dec 18 05:34:53 UTC 2019
ppc64le ppc64le ppc64le GNU/Linux
Machine Type = all P9 supporting opencapi: mihawk and AC922 (witherspoon)
---Debugger---
A debugger is not configured
Stack trace output:
no
Oops output:
no
System Dump Info:
The system is not configured to capture a system dump.
*Additional Instructions for [email protected]:
-Attach sysctl -a output output to the bug.
== Comment: #1 - Frederic Barrat <[email protected]> - 2020-01-27
11:00:49 ==
The linux code in question has been on the mailing list for a while and is
expected to be merged in the 5.6 merge window opening today.
Here is a link to the patches on the mailing list. I'll post the official
commit IDs once they are known.
http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=144336
Once merged upstream, is it possible to add them to the 20.04 kernel?
Of course, I'll handle the backport if it's needed.
== Comment: #3 - Frederic Barrat <[email protected]> - 2020-01-30
02:51:05 ==
The patches have been merged in the powerpc maintainer's 'next' tree and will
be in kernel 5.6 and now have official commit IDs:
05dd7da76986 powerpc/powernv/ioda: Fix ref count for devices with their own PE
80f1ff83fa11 powerpc/powernv/ioda: Protect PE list
c1a2feade085 powerpc/powernv/ioda: set up PE on opencapi device when enabling
f724385fea01 powerpc/powernv/ioda: Release opencapi device
bbb789046084 powerpc/powernv/ioda: Find opencapi slot for a device node
658ab186dd22 pci/hotplug/pnv-php: Remove erroneous warning
323c2a26ff43 pci/hotplug/pnv-php: Improve error msg on power state change
failure
ea53919b15bf pci/hotplug/pnv-php: Register opencapi slots
be1611e043de pci/hotplug/pnv-php: Relax check when disabling slot
748ac391ab9a pci/hotplug/pnv-php: Wrap warnings in macro
49ce94b8677c ocxl: Add PCI hotplug dependency to Kconfig
They apply cleanly on kernel v5.4 and v5.5, starting from the bottom.
They impact powerpc-only code and even more specifically the powernv platform.
The PCI hotplug module modifications for powernv are to make the hotplug
driver aware of the new opencapi slots.
The "ioda" modifications are to manage the state of opencapi devices
properly, since they can now be destroyed and recreated when the opencapi link
is reset.
Could the patches be added to the kernel which will be used for Ubuntu 20.04?
Thanks
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