Re: [PATCH -v4 2/2] PCIe: Add PCIe runtime D3cold support

Rafael J. Wysocki
2012-05-30T21:44:29Z

On Tuesday, May 22, 2012, Rafael J. Wysocki wrote:
> On Friday, May 18, 2012, Huang Ying wrote:
> > This patch adds runtime D3cold support to PCIe bus. D3cold is the
> > deepest power saving state for PCIe devices. Where the main PCIe link
> > will be powered off totally, so before the PCIe main link is powered
> > on again, you can not access the device, even the configuration space,
> > which is still accessible in D3hot. Because the main PCIe link is not
> > available, the PCI PM registers can not be used to put device into/out
> > of D3cold state, that will be done by platform logic such as ACPI
> > _PR3.
> >
> > To support remote wake up in D3cold, aux power is supplied, and a
> > side-band pin: WAKE# is used to notify remote wake up event, the pin
> > is usually connected to platform logic such as ACPI GPE. This is
> > quite different with other power saving states, where remote wake up
> > is notified via PME message through the PCIe main link.
> >
> > PCIe devices in plug-in slot usually has no direct platform logic, for
> > example, there is usually no ACPI _PR3 for them. The D3cold support
> > for these devices can be done via the PCIe port connected to it. When
> > power on/off the PCIe port, the corresponding PCIe devices are powered
> > on/off too. And the remote wake up event from PCIe device will be
> > notified to the corresponding PCIe port.
> >
> > The PCI subsystem D3cold support and corresponding ACPI platform
> > support is implemented in the patch. Including the support for PCIe
> > devices in plug-in slot.
> >
> > For more information about PCIe D3cold and corresponding ACPI support,
> > please refer to:
> >
> > - PCI Express Base Specification Revision 2.0
> > - Advanced Configuration and Power Interface Specification Revision 5.0
> >
> > Originally-by: Zheng Yan <zheng.z.yan@intel.com>
> > Signed-off-by: Huang Ying <ying.huang@intel.com>
>
> Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>

On a second thought ...

> > ---
> > drivers/pci/pci-acpi.c | 23 +++++++-
> > drivers/pci/pci-driver.c | 3 +
> > drivers/pci/pci-sysfs.c | 29 ++++++++++
> > drivers/pci/pci.c | 110 +++++++++++++++++++++++++++++++++++++----
> > drivers/pci/pci.h | 1
> > drivers/pci/pcie/portdrv_pci.c | 44 ++++++++++++++--
> > include/linux/pci.h | 16 ++++-
> > 7 files changed, 205 insertions(+), 21 deletions(-)
> >
> > --- a/drivers/pci/pci-acpi.c
> > +++ b/drivers/pci/pci-acpi.c
> > @@ -48,6 +48,12 @@ static void pci_acpi_wake_dev(acpi_handl
> > if (event != ACPI_NOTIFY_DEVICE_WAKE || !pci_dev)
> > return;
> >
> > + if (pci_dev->current_state == PCI_D3cold) {
> > + pci_wakeup_event(pci_dev);
> > + pm_runtime_resume(&pci_dev->dev);
> > + return;
> > + }
> > +
> > if (!pci_dev->pm_cap || !pci_dev->pme_support
> > || pci_check_pme_status(pci_dev)) {
> > if (pci_dev->pme_poll)
> > @@ -187,10 +193,13 @@ acpi_status pci_acpi_remove_pm_notifier(
> >
> > static pci_power_t acpi_pci_choose_state(struct pci_dev *pdev)
> > {
> > - int acpi_state;
> > + int acpi_state, d_max;
> >
> > - acpi_state = acpi_pm_device_sleep_state(&pdev->dev, NULL,
> > - ACPI_STATE_D3);

I wonder what tree this patch is against? The code above doesn't seem to
be present in the current mainline.

Thanks,
Rafael