Hi Mario, On Tue, Sep 9, 2025 at 9:16 PM Mario Limonciello (AMD) <supe...@kernel.org> wrote: > > A variety of issues both in function and in power consumption have been > raised as a result of devices not being put into a low power state when > the system is powered off. > > There have been some localized changes[1] to PCI core to help these issues, > but they have had various downsides. > > This series instead uses the driver hibernate flows when the system is > being powered off or halted. This lines up the behavior with what other > operating systems do as well. If for some reason that fails or is not > supported, run driver shutdown() callbacks. > > Rafael did mention in earlier versions of the series concerns about > regression risk. He was looking for thoughts from Greg who isn't against > it but also isn't sure about how to maintain it. [1] > > This has been validated by me and several others in AMD > on a variety of AMD hardware platforms. It's been validated by some > community members on their Intel hardware. To my knowledge it has not > been validated on non-x86.
Still, the patches need more work (see my replies to the relevant patches). > On my development laptop I have also contrived failures in the hibernation > callbacks to make sure that the fallback to shutdown callback works. > > In order to assist with potential regressions the series also includes > documentation to help with getting a kernel log at shutdown after > the disk is unmounted. > > Cc: AceLan Kao <acelan....@canonical.com> > Cc: Kai-Heng Feng <kaihe...@nvidia.com> > Cc: Mark Pearson <mpearson-len...@squebb.ca> > Cc: Merthan Karakaş <m3rth...@gmail.com> > Cc: Eric Naim <dn...@cachyos.org> > Link: https://lore.kernel.org/linux-usb/2025090852-coma-tycoon-9f37@gregkh/ > [1] > --- > v6->v7: > * Add documentation on how to debug a shutdown hang > * Adjust commit messages per feedback from Bjorn > > Mario Limonciello (AMD) (12): > PM: Introduce new PMSG_POWEROFF event > scsi: Add PM_EVENT_POWEROFF into suspend callbacks > usb: sl811-hcd: Add PM_EVENT_POWEROFF into suspend callbacks > USB: Pass PMSG_POWEROFF event to suspend_common() > PCI/PM: Disable device wakeups when halting or powering off system > PCI/PM: Split out code from pci_pm_suspend_noirq() into helper > PCI/PM: Run bridge power up actions as part of restore phase > PCI/PM: Use pci_power_manageable() in pci_pm_poweroff_noirq() > PCI: Put PCIe bridges with downstream devices into D3 at hibernate > drm/amd: Avoid evicting resources at S5 > PM: Use hibernate flows for system power off > Documentation: power: Add document on debugging shutdown hangs If I were you, I'd split this series into 3 parts. The first part would be the addition of PMSG_POWEROFF just for hibernation, which should not be objectionable (the first 4 patches above). The next one would be changes to allow PCI bridges to go into D3hot/cold during the last stage of hibernation (the "power-off" transition). This can be justified by itself even before starting to use the same power-off flow for the last stage of hibernation and for system power-down. The last one would be the hibernation/power-down integration. Each of the above can be posted separately and arguably you need to get the first part in before the other two and the second part in before the third one, preferably not in the same cycle. This way, if there are any regressions in the first two parts, there will be at least some time to address them before the last part goes in. Thanks!
