On 9/10/25 1:11 PM, Rafael J. Wysocki wrote:
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).
Yes, thanks for the review.
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!
Thanks for this proposal.
I do like the idea of splitting it in 3 parts to give time for
regression control.
It's getting close to the end of this cycle, would you be opposed to a
re-spun first 4 patches for 6.18?
Thanks,
