On Thu, 10 Aug 2023 13:29:44 -0500 Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > On Thu, Aug 03, 2023 at 11:12:31AM -0600, Alex Williamson wrote: > > Since v5.19, vfio-pci makes use of runtime power management on devices. > > This has the effect of potentially putting entire sub-hierarchies into > > lower power states, which has exposed some gaps in the PCI subsystem > > around power management support. > > > > The first issue is that lspci accesses the VPD sysfs interface, which > > does not provide the same power management wrappers as general config > > space. > > > > The next covers PME, where we attempt to skip devices based on their PCI > > power state, but don't protect changes to that state or look at the > > overall runtime power management state of the device. > > > > This latter patch addresses the issue noted by Eric in the follow-ups to > > v1 linked below. > > > > These patches are logically independent, but only together resolve an > > issue on Eric's system where a pair of endpoints bound to vfio-pci and > > unused by userspace drivers trigger faults through lspci and PME > > polling. Thanks, > > > > Alex > > > > v1: https://lore.kernel.org/all/20230707151044.1311544-1-alex.williamson@xxxxxxxxxx/ > > > > Alex Williamson (2): > > PCI/VPD: Add runtime power management to sysfs interface > > PCI: Fix runtime PM race with PME polling > > > > drivers/pci/pci.c | 23 ++++++++++++++++------- > > drivers/pci/vpd.c | 34 ++++++++++++++++++++++++++++++++-- > > 2 files changed, 48 insertions(+), 9 deletions(-) > > Applied with the tweak below to pci/vpd for v6.6, thanks! The idea is > to match the pci_get_func0_dev() so the get/put balance is clear > without having to analyze PCI_DEV_FLAGS_VPD_REF_F0 usage: > > - if (dev != vpd_dev) > + if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) > Looks good, thanks! Alex
