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    Subject[RFC][PATCH 1/2] PCI PM: Export platform_pci_set_power_state()
    Date
    From: Rafael J. Wysocki <rjw@sisk.pl>

    The radeonfb driver needs to program the device's PMCSR directly due
    to some quirky hardware it has to handle (see
    http://bugzilla.kernel.org/show_bug.cgi?id=12846 for details) and
    after doing that it needs to call the platform (usually ACPI) to
    finish the power transition of the device. Currently it uses
    pci_set_power_state() for this purpose, however making a specific
    assumption about the internal behavior of this function, which has
    changed recently so that this assumption is no longer satisfied.
    For this reason, change platform_pci_set_power_state() into an
    exported function so that the radeonfb driver can use it directly
    instead of calling it via pci_set_power_state().

    Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
    ---
    drivers/pci/pci.c | 68 +++++++++++++++++++++++++++++-----------------------
    include/linux/pci.h | 1
    2 files changed, 40 insertions(+), 29 deletions(-)

    Index: linux-2.6/drivers/pci/pci.c
    ===================================================================
    --- linux-2.6.orig/drivers/pci/pci.c
    +++ linux-2.6/drivers/pci/pci.c
    @@ -398,12 +398,6 @@ static inline bool platform_pci_power_ma
    return pci_platform_pm ? pci_platform_pm->is_manageable(dev) : false;
    }

    -static inline int platform_pci_set_power_state(struct pci_dev *dev,
    - pci_power_t t)
    -{
    - return pci_platform_pm ? pci_platform_pm->set_state(dev, t) : -ENOSYS;
    -}
    -
    static inline pci_power_t platform_pci_choose_state(struct pci_dev *dev)
    {
    return pci_platform_pm ?
    @@ -540,6 +534,31 @@ void pci_update_current_state(struct pci
    }

    /**
    + * platform_pci_set_power_state - Call platform to change device power state
    + * @dev: PCI device to handle
    + * @state: State to put the device into
    + *
    + * Allow the platform to change the power state of the device, for example via
    + * ACPI _PR0, _PS0 or some such.
    + */
    +int platform_pci_set_power_state(struct pci_dev *dev, pci_power_t state)
    +{
    + int error = 0;
    +
    + if (!pci_platform_pm)
    + return -ENOSYS;
    +
    + if (pci_platform_pm->is_manageable(dev))
    + error = pci_platform_pm->set_state(dev, state);
    +
    + if (!error)
    + pci_update_current_state(dev, state);
    +
    + return error;
    +}
    +EXPORT_SYMBOL_GPL(platform_pci_set_power_state);
    +
    +/**
    * pci_set_power_state - Set the power state of a PCI device
    * @dev: PCI device to handle.
    * @state: PCI power state (D0, D1, D2, D3hot) to put the device into.
    @@ -556,7 +575,7 @@ void pci_update_current_state(struct pci
    */
    int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
    {
    - int error;
    + int error, platform_error = -ENODEV;

    /* bound the state we're entering */
    if (state > PCI_D3hot)
    @@ -570,36 +589,27 @@ int pci_set_power_state(struct pci_dev *
    * it into D0 (which would only happen on boot).
    */
    return 0;
    + else if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
    + /*
    + * This device is quirked not to be put into D3, so don't put it
    + * in D3
    + */
    + return 0;

    /* Check if we're already there */
    if (dev->current_state == state)
    return 0;

    - if (state == PCI_D0) {
    - /*
    - * Allow the platform to change the state, for example via ACPI
    - * _PR0, _PS0 and some such, but do not trust it.
    - */
    - int ret = platform_pci_power_manageable(dev) ?
    - platform_pci_set_power_state(dev, PCI_D0) : 0;
    - if (!ret)
    - pci_update_current_state(dev, PCI_D0);
    - }
    - /* This device is quirked not to be put into D3, so
    - don't put it in D3 */
    - if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
    - return 0;
    + if (state == PCI_D0)
    + platform_error = platform_pci_set_power_state(dev, PCI_D0);

    error = pci_raw_set_power_state(dev, state);

    - if (state > PCI_D0 && platform_pci_power_manageable(dev)) {
    - /* Allow the platform to finalize the transition */
    - int ret = platform_pci_set_power_state(dev, state);
    - if (!ret) {
    - pci_update_current_state(dev, state);
    - error = 0;
    - }
    - }
    + if (state > PCI_D0)
    + platform_error = platform_pci_set_power_state(dev, state);
    +
    + if (!platform_error)
    + error = 0;

    return error;
    }
    Index: linux-2.6/include/linux/pci.h
    ===================================================================
    --- linux-2.6.orig/include/linux/pci.h
    +++ linux-2.6/include/linux/pci.h
    @@ -689,6 +689,7 @@ size_t pci_get_rom_size(struct pci_dev *
    /* Power management related routines */
    int pci_save_state(struct pci_dev *dev);
    int pci_restore_state(struct pci_dev *dev);
    +int platform_pci_set_power_state(struct pci_dev *dev, pci_power_t state);
    int pci_set_power_state(struct pci_dev *dev, pci_power_t state);
    pci_power_t pci_choose_state(struct pci_dev *dev, pm_message_t state);
    bool pci_pme_capable(struct pci_dev *dev, pci_power_t state);

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