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PCI: PM: Avoid skipping bus-level PM on platforms without ACPI

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There are platforms that do not call pm_set_suspend_via_firmware(),
so pm_suspend_via_firmware() returns 'false' on them, but the power
states of PCI devices (PCIe ports in particular) are changed as a
result of powering down core platform components during system-wide
suspend.  Thus the pm_suspend_via_firmware() checks in
pci_pm_suspend_noirq() and pci_pm_resume_noirq() introduced by
commit 3e26c5feed ("PCI: PM: Skip devices in D0 for suspend-to-
idle") are not sufficient to determine that devices left in D0
during suspend will remain in D0 during resume and so the bus-level
power management can be skipped for them.

For this reason, introduce a new global suspend flag,
PM_SUSPEND_FLAG_NO_PLATFORM, set it for suspend-to-idle only
and replace the pm_suspend_via_firmware() checks mentioned above
with checks against this flag.

Fixes: 3e26c5feed ("PCI: PM: Skip devices in D0 for suspend-to-idle")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
This commit is contained in:
Rafael J. Wysocki 2019-06-26 00:20:23 +02:00
parent 4b972a01a7
commit 471a739a47
3 changed files with 31 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
drivers/pci/pci-driver.c
View file

@ -859,7 +859,7 @@ static int pci_pm_suspend_noirq(struct device *dev)
pci_dev->bus->self->skip_bus_pm = true;
}
if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) {
if (pci_dev->skip_bus_pm && pm_suspend_no_platform()) {
dev_dbg(dev, "PCI PM: Skipped\n");
goto Fixup;
}
@ -914,10 +914,10 @@ static int pci_pm_resume_noirq(struct device *dev)
/*
* In the suspend-to-idle case, devices left in D0 during suspend will
* stay in D0, so it is not necessary to restore or update their
* configuration here and attempting to put them into D0 again may
* confuse some firmware, so avoid doing that.
* configuration here and attempting to put them into D0 again is
* pointless, so avoid doing that.
*/
if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware())
if (!(pci_dev->skip_bus_pm && pm_suspend_no_platform()))
pci_pm_default_resume_early(pci_dev);
pci_fixup_device(pci_fixup_resume_early, pci_dev);

26
include/linux/suspend.h
View file

@ -209,8 +209,9 @@ extern int suspend_valid_only_mem(suspend_state_t state);
extern unsigned int pm_suspend_global_flags;
#define PM_SUSPEND_FLAG_FW_SUSPEND (1 << 0)
#define PM_SUSPEND_FLAG_FW_RESUME (1 << 1)
#define PM_SUSPEND_FLAG_FW_SUSPEND BIT(0)
#define PM_SUSPEND_FLAG_FW_RESUME BIT(1)
#define PM_SUSPEND_FLAG_NO_PLATFORM BIT(2)
static inline void pm_suspend_clear_flags(void)
{
@ -227,6 +228,11 @@ static inline void pm_set_resume_via_firmware(void)
pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME;
}
static inline void pm_set_suspend_no_platform(void)
{
pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM;
}
/**
* pm_suspend_via_firmware - Check if platform firmware will suspend the system.
*
@ -268,6 +274,22 @@ static inline bool pm_resume_via_firmware(void)
return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME);
}
/**
* pm_suspend_no_platform - Check if platform may change device power states.
*
* To be called during system-wide power management transitions to sleep states
* or during the subsequent system-wide transitions back to the working state.
*
* Return 'true' if the power states of devices remain under full control of the
* kernel throughout the system-wide suspend and resume cycle in progress (that
* is, if a device is put into a certain power state during suspend, it can be
* expected to remain in that state during resume).
*/
static inline bool pm_suspend_no_platform(void)
{
return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM);
}
/* Suspend-to-idle state machnine. */
enum s2idle_states {
S2IDLE_STATE_NONE, /* Not suspended/suspending. */

3
kernel/power/suspend.c
View file

@ -493,6 +493,9 @@ int suspend_devices_and_enter(suspend_state_t state)
pm_suspend_target_state = state;
if (state == PM_SUSPEND_TO_IDLE)
pm_set_suspend_no_platform();
error = platform_suspend_begin(state);
if (error)
goto Close;