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| author | Rafael J. Wysocki <rjw@sisk.pl> | 2009-03-16 22:40:36 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rjw@sisk.pl> | 2009-03-30 21:46:56 +0200 |
| commit | 4a865905f685eaefaedf6ade362323dc52aa703b (patch) | |
| tree | 4b0b38ffe0e4f00a13af03ac55957aa32dc9c8ac /drivers | |
| parent | 46939f8b15e44f065d052e89ea4f2adc81fdc740 (diff) | |
| download | linux-4a865905f685eaefaedf6ade362323dc52aa703b.tar.bz2 | |
PCI PM: Make pci_set_power_state() handle devices with no PM support
There is a problem with PCI devices without any PM support (either
native or through the platform) that pci_set_power_state() always
returns error code for them, even if they are being put into D0.
However, such devices are always in D0, so pci_set_power_state()
should return success when attempting to put such a device into D0.
It also should update the current_state field for these devices as
appropriate. This modification is necessary so that the standard
configuration registers of these devices are successfully restored by
pci_restore_standard_config() during the "early" phase of resume.
In addition, pci_set_power_state() should check the value of
current_state before calling the platform to change the power state
of the device to avoid doing that unnecessarily.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/pci/pci.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index a4ecc2f15126..979ceb1d37e8 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -439,6 +439,10 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) u16 pmcsr; bool need_restore = false; + /* Check if we're already there */ + if (dev->current_state == state) + return 0; + if (!dev->pm_cap) return -EIO; @@ -449,10 +453,7 @@ static int pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state) * Can enter D0 from any state, but if we can only go deeper * to sleep if we're already in a low power state */ - if (dev->current_state == state) { - /* we're already there */ - return 0; - } else if (state != PCI_D0 && dev->current_state <= PCI_D3cold + if (state != PCI_D0 && dev->current_state <= PCI_D3cold && dev->current_state > state) { dev_err(&dev->dev, "invalid power transition " "(from state %d to %d)\n", dev->current_state, state); @@ -570,12 +571,17 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state) */ return 0; - if (state == PCI_D0 && platform_pci_power_manageable(dev)) { + /* 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_set_power_state(dev, PCI_D0); + 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); } |