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authorRafael J. Wysocki <rjw@sisk.pl>2009-03-16 22:40:36 +0100
committerRafael J. Wysocki <rjw@sisk.pl>2009-03-30 21:46:56 +0200
commit4a865905f685eaefaedf6ade362323dc52aa703b (patch)
tree4b0b38ffe0e4f00a13af03ac55957aa32dc9c8ac
parent46939f8b15e44f065d052e89ea4f2adc81fdc740 (diff)
downloadop-kernel-dev-4a865905f685eaefaedf6ade362323dc52aa703b.zip
op-kernel-dev-4a865905f685eaefaedf6ade362323dc52aa703b.tar.gz
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>
-rw-r--r--drivers/pci/pci.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a4ecc2f..979ceb1 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);
}
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