** Changed in: ubuntu-power-systems
Status: Triaged => In Progress
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https://bugs.launchpad.net/bugs/1788549
Title:
powerpc/powernv/pci: Work around races in PCI bridge enabling
Status in The Ubuntu-power-systems project:
In Progress
Status in linux package in Ubuntu:
In Progress
Status in linux source package in Xenial:
In Progress
Status in linux source package in Bionic:
In Progress
Status in linux source package in Cosmic:
In Progress
Bug description:
== Comment: #0 - Michael Ranweiler <mranw...@us.ibm.com> - 2018-08-21
13:52:03 ==
+++ This bug was initially created as a clone of Bug #170766 +++
Please apply the following kernel patch:
https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next&id=db2173198b9513f7add8009f225afa1f1c79bcc6
powerpc/powernv/pci: Work around races in PCI bridge enabling
The generic code is racy when multiple children of a PCI bridge try to
enable it simultaneously.
This leads to drivers trying to access a device through a
not-yet-enabled bridge, and this EEH errors under various
circumstances when using parallel driver probing.
There is work going on to fix that properly in the PCI core but it
will take some time.
x86 gets away with it because (outside of hotplug), the BIOS enables
all the bridges at boot time.
This patch does the same thing on powernv by enabling all bridges that
have child devices at boot time, thus avoiding subsequent races. It's
suitable for backporting to stable and distros, while the proper PCI
fix will probably be significantly more invasive.
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: sta...@vger.kernel.org
Signed-off-by: Michael Ellerman <m...@ellerman.id.au>
== Comment: #2 - Michael Ranweiler <mranw...@us.ibm.com> - 2018-08-21
18:23:35 ==
This has some fuzz and also move it back from the pci macro to dev_err so
we'll attach the backported patch.
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