** Changed in: linux (Ubuntu Plucky)
Status: Triaged => Fix Committed
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https://bugs.launchpad.net/bugs/2117494
Title:
[Regression Updates] "PCI: Explicitly put devices into D0 when
initializing" breaks pci-pass-through in QEMU/KVM
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Noble:
Triaged
Status in linux source package in Plucky:
Fix Committed
Bug description:
[SRU Justification]
Impact: Reported regression to PCI pass-through in QEMU/KVM
(https://lists.ubuntu.com/archives/kernel-team/2025-July/161565.html)
which was caused by changes to fix suspend/resume on disks with BIOS
password set (bug #2110090).
Fix: Upstream fix from 6.16-rc3 addressing the issue (see below)
Testcase: Requires to set up a VM with PCI pass-through.
Regression potential: Things related to PCI power management (devices
not being initialized or not properly resuming after suspend).
--- original description ---
From: Thomas Lamprecht <[email protected]>
Subject: Re: [PATCH 1/1][SRU][N] PCI: Explicitly put devices into D0 when
initializing
...
FYI: This causes regressions on PCI passthrough to QEMU/KVM, among other
things. A colleague found that the following patch on top fixes it here:
commit 907a7a2e5bf40c6a359b2f6cc53d6fdca04009e0
Author: Mario Limonciello <[email protected]>
Date: Wed Jun 11 18:31:16 2025 -0500
PCI/PM: Set up runtime PM even for devices without PCI PM
4d4c10f763d7 ("PCI: Explicitly put devices into D0 when initializing")
intended to put PCI devices into D0, but in doing so unintentionally
changed runtime PM initialization not to occur on devices that don't
support PCI PM. This caused a regression in vfio-pci due to an imbalance
with its use.
Adjust the logic in pci_pm_init() so that even if PCI PM isn't supported
runtime PM is still initialized.
Fixes: 4d4c10f763d7 ("PCI: Explicitly put devices into D0 when
initializing")
Reported-by: Giovanni Cabiddu <[email protected]>
Closes:
https://lore.kernel.org/linux-pci/[email protected]/T/#m7e8929d6421690dc8bd6dc639d86c2b4db27cbc4
Reported-by: Nicolas Dichtel <[email protected]>
Closes:
https://lore.kernel.org/linux-pci/[email protected]/T/#m40d277dcdb9be64a1609a82412d1aa906263e201
Signed-off-by: Mario Limonciello <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Tested-by: Giovanni Cabiddu <[email protected]>
Tested-by: Nicolas Dichtel <[email protected]>
Reviewed-by: Kuppuswamy Sathyanarayanan
<[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Cc: Alex Williamson <[email protected]>
Link: https://patch.msgid.link/[email protected]
Same holds for the Plucky backport in patch mail id:
<[email protected]>
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