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


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