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    SubjectRe: [RFC PATCH] set current_state to D0 in register_slot
    On Fri, 4 Mar 2011, Jesse Barnes wrote:
    > On Mon, 28 Feb 2011 16:20:11 +0000
    > Stefano Stabellini <stefano.stabellini@eu.citrix.com> wrote:
    >
    > > Hi all,
    > > if a device doesn't support power management (pm_cap == 0) but it is
    > > acpi_pci_power_manageable() because there is a _PS0 method declared for
    > > it and _EJ0 is also declared for the slot then nobody is going to set
    > > current_state = PCI_D0 for this device. This is what I think it is
    > > happening:
    > >
    > >
    > > pci_enable_device
    > > |
    > > __pci_enable_device_flags
    > > /* here we do not set current_state because !pm_cap */
    > > |
    > > do_pci_enable_device
    > > |
    > > pci_set_power_state
    > > |
    > > __pci_start_power_transition
    > > |
    > > pci_platform_power_transition
    > > /* platform_pci_power_manageable() calls acpi_pci_power_manageable that
    > > * returns true */
    > > |
    > > platform_pci_set_power_state
    > > /* acpi_pci_set_power_state gets called and does nothing because the
    > > * acpi device has _EJ0, see the comment "If the ACPI device has _EJ0,
    > > * ignore the device" */
    > >
    > >
    > > at this point if we refer to the commit message that introduced the
    > > comment above (10b3dcae0f275e2546e55303d64ddbb58cec7599), it is up to
    > > the hotplug driver to set the state to D0.
    > > However AFAICT the pci hotplug driver never does, in fact
    > > drivers/pci/hotplug/acpiphp_glue.c:register_slot sets the slot flags to
    > > (SLOT_ENABLED | SLOT_POWEREDON) but it does not set the pci device
    > > current state to PCI_D0.
    > >
    > > So my proposed fix is also to set current_state = PCI_D0 in
    > > register_slot.
    > > Comments are very welcome.
    > >
    > >
    > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
    >
    > Yeah, looks fine. ACPIPHP is happy for the attention. :)

    Great, thanks!
    Would you be OK with taking this patch in your tree?
    Or do you prefer me to send to it Linus myself?


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