Re: [PATCH v6 00/11] Improvements to S5 power consumption

Greg Kroah-Hartman
2025-09-06T12:20:03Z

On Wed, Sep 03, 2025 at 01:14:18PM +0200, Rafael J. Wysocki wrote:
> On Wed, Sep 3, 2025 at 6:41 AM Mario Limonciello <superm1@kernel.org> wrote:
> >
> > On 8/17/2025 9:00 PM, Mario Limonciello (AMD) 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 tries to use the S4 flow when the system is being
> > > powered off. This lines up the behavior with what other operating systems
> > > do as well. If for some reason that fails or is not supported, run their
> > > shutdown() callbacks.
> > >
> > > Cc: AceLan Kao <acelan.kao@canonical.com>
> > > Cc: Kai-Heng Feng <kaihengf@nvidia.com>
> > > Cc: Mark Pearson <mpearson-lenovo@squebb.ca>
> > > Cc: Merthan Karakaş <m3rthn.k@gmail.com>
> > > Cc: Eric Naim <dnaim@cachyos.org>
> > > ---
> > > v5->v6:
> > > * Fix for LKP robot issue
> > > * Some commit message changes
> > > * Rebase on 6.17-rc2
> > >
> > > Mario Limonciello (AMD) (11):
> > > 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() for poweroff with S4
> > > flow
> > > PCI: PM: Disable device wakeups when halting system through S4 flow
> > > 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
> > >
> > > drivers/base/power/main.c | 7 ++
> > > drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 +
> > > drivers/pci/pci-driver.c | 99 +++++++++++++++-------
> > > drivers/scsi/mesh.c | 1 +
> > > drivers/scsi/stex.c | 1 +
> > > drivers/usb/core/hcd-pci.c | 11 ++-
> > > drivers/usb/host/sl811-hcd.c | 1 +
> > > include/linux/pm.h | 5 +-
> > > include/trace/events/power.h | 3 +-
> > > kernel/reboot.c | 6 ++
> > > 10 files changed, 103 insertions(+), 35 deletions(-)
> > >
> >
> > Rafael, Bjorn,
> >
> > Any feedback for this series?
>
> I still have the same basic concern as before: It is an intrusive
> change likely to cause regressions to occur.
>
> It also changes the driver ABI quite dramatically because different
> callbacks will now be used for system shutdown and kexec, for example,
> at least on some platforms.
>
> Frankly, I'd like to know Greg's and Danilo's opinions on the direction here.
>

I've been ignoring this, sorry. Can someone resend the series and ask
for my review then?

thanks,

greg k-h