From: Rafael J. Wysocki <rjw@xxxxxxx> The story in http://bugzilla.kernel.org/show_bug.cgi?id=12846 shows that setting the power state of a PCI device may sometimes require multiple attempts to program the device's PMCSR and and/or an delay longer than the default one. For this reason, introduce __pci_set_power_state() that will take two additional arguments, the number of attempts to program the power state of the device to be made and the delay after writing a new value to the device's PMCSR. Redefine pci_set_power_state() as __pci_set_power_state() using the default values of the new arguments. Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> --- drivers/pci/pci.c | 63 +++++++++++++++++++++++++++++++++++++++------------- include/linux/pci.h | 7 ++++- 2 files changed, 54 insertions(+), 16 deletions(-) Index: linux-2.6/drivers/pci/pci.c =================================================================== --- linux-2.6.orig/drivers/pci/pci.c +++ linux-2.6/drivers/pci/pci.c @@ -426,6 +426,9 @@ static inline int platform_pci_sleep_wak * given PCI device * @dev: PCI device to handle. * @state: PCI power state (D0, D1, D2, D3hot) to put the device into. + * @attempts: How many times to try to change the power state of the device + * @delay: Delay after programming the new power state, in miliseconds (0 means + * use default) * * RETURN VALUE: * -EINVAL if the requested state is invalid. @@ -434,9 +437,13 @@ static inline int platform_pci_sleep_wak * 0 if device already is in the requested state. * 0 if device's power state has been successfully changed. */ -static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) +static int pci_raw_set_power_state( + struct pci_dev *dev, + pci_power_t state, + unsigned int attempts, + unsigned int delay) { - u16 pmcsr; + u16 pmcsr, new_pmcsr; bool need_restore = false; /* Check if we're already there */ @@ -488,17 +495,36 @@ static int pci_raw_set_power_state(struc break; } - /* enter specified state */ - pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr); + do { + /* Program the requested state */ + pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr); - /* Mandatory power management transition delays */ - /* see PCI PM 1.1 5.6.1 table 18 */ - if (state == PCI_D3hot || dev->current_state == PCI_D3hot) - msleep(pci_pm_d3_delay); - else if (state == PCI_D2 || dev->current_state == PCI_D2) - udelay(PCI_PM_D2_DELAY); + /* + * If delay has not been specified, use mandatory PCI power + * management transition delays (see PCI PM 1.1 5.6.1 table 18). + */ + if (delay) + msleep(delay); + else if (state == PCI_D3hot || dev->current_state == PCI_D3hot) + msleep(pci_pm_d3_delay); + else if (state == PCI_D2 || dev->current_state == PCI_D2) + udelay(PCI_PM_D2_DELAY); + + /* Check if the power state has actually changed */ + pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, + &new_pmcsr); + if (pmcsr == new_pmcsr) { + dev->current_state = state; + break; + } + } while (--attempts); - dev->current_state = state; + if (pmcsr != new_pmcsr) { + dev->current_state = (new_pmcsr & PCI_PM_CTRL_STATE_MASK); + dev_warn(&dev->dev, + "failed to set power state to D%d, is D%d\n", state, + dev->current_state); + } /* According to section 5.4.1 of the "PCI BUS POWER MANAGEMENT * INTERFACE SPECIFICATION, REV. 1.2", a device transitioning @@ -540,9 +566,12 @@ void pci_update_current_state(struct pci } /** - * pci_set_power_state - Set the power state of a PCI device + * __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. + * @attempts: How many times to try to change the power state of the device. + * @delay: Delay after programming the new power state, in miliseconds (0 means + * use default). * * Transition a device to a new power state, using the platform formware and/or * the device's PCI PM registers. @@ -554,7 +583,11 @@ void pci_update_current_state(struct pci * 0 if device already is in the requested state. * 0 if device's power state has been successfully changed. */ -int 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, + unsigned int attempts, + unsigned int delay) { int error; @@ -590,7 +623,7 @@ int pci_set_power_state(struct pci_dev * if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3)) return 0; - error = pci_raw_set_power_state(dev, state); + error = pci_raw_set_power_state(dev, state, attempts, delay); if (state > PCI_D0 && platform_pci_power_manageable(dev)) { /* Allow the platform to finalize the transition */ @@ -603,6 +636,7 @@ int pci_set_power_state(struct pci_dev * return error; } +EXPORT_SYMBOL(__pci_set_power_state); /** * pci_choose_state - Choose the power state of a PCI device @@ -2409,7 +2443,6 @@ EXPORT_SYMBOL(pci_assign_resource); EXPORT_SYMBOL(pci_find_parent_resource); EXPORT_SYMBOL(pci_select_bars); -EXPORT_SYMBOL(pci_set_power_state); EXPORT_SYMBOL(pci_save_state); EXPORT_SYMBOL(pci_restore_state); EXPORT_SYMBOL(pci_pme_capable); Index: linux-2.6/include/linux/pci.h =================================================================== --- linux-2.6.orig/include/linux/pci.h +++ linux-2.6/include/linux/pci.h @@ -689,7 +689,12 @@ 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 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, + unsigned int attempts, unsigned int delay); +static inline int pci_set_power_state(struct pci_dev *dev, pci_power_t state) +{ + return __pci_set_power_state(dev, state, 1, 0); +} 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); void pci_pme_active(struct pci_dev *dev, bool enable); -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
