[patch 2.6.25-rc6 4/7] USB uses pci_choose_state()

David Brownell
2008-03-20T21:30:44Z

Given a preceding patch that makes pci_choose_state() behave sanely,
use it to select the appropriate PCI_Dx state to use when suspending
a host controller.

USB hosts may now use states like PCI_D1 and PCI_D2, where appropriate.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
---
drivers/usb/core/hcd-pci.c | 25 ++++++++-----------------
1 file changed, 8 insertions(+), 17 deletions(-)

--- g26.orig/drivers/usb/core/hcd-pci.c 2008-02-24 02:02:45.000000000 -0800
+++ g26/drivers/usb/core/hcd-pci.c 2008-02-24 02:08:08.000000000 -0800
@@ -224,18 +224,6 @@ int usb_hcd_pci_suspend(struct pci_dev *
}
synchronize_irq(dev->irq);

- /* FIXME until the generic PM interfaces change a lot more, this
- * can't use PCI D1 and D2 states. For example, the confusion
- * between messages and states will need to vanish, and messages
- * will need to provide a target system state again.
- *
- * It'll be important to learn characteristics of the target state,
- * especially on embedded hardware where the HCD will often be in
- * charge of an external VBUS power supply and one or more clocks.
- * Some target system states will leave them active; others won't.
- * (With PCI, that's often handled by platform BIOS code.)
- */
-
/* even when the PCI layer rejects some of the PCI calls
* below, HCs can try global suspend and reduce DMA traffic.
* PM-sensitive HCDs may already have done this.
@@ -248,6 +236,7 @@ int usb_hcd_pci_suspend(struct pci_dev *
* low power state, if the hardware allows.
*/
if (hcd->state == HC_STATE_SUSPENDED) {
+ pci_power_t d_state;

/* no DMA or IRQs except when HC is active */
if (dev->current_state == PCI_D0) {
@@ -265,27 +254,29 @@ int usb_hcd_pci_suspend(struct pci_dev *
dev_dbg(hcd->self.controller, "--> PCI D0/legacy\n");
goto done;
}
+ d_state = pci_choose_state(dev, message);

- /* NOTE: dev->current_state becomes nonzero only here, and
- * only for devices that support PCI PM. Also, exiting
+ /* NOTE: dev->current_state becomes nonzero only here, using
+ * D3hot unless the platform chooses D2 or D1. Also, exiting
* PCI_D3 (but not PCI_D1 or PCI_D2) is allowed to reset
* some device state (e.g. as part of clock reinit).
*/
- retval = pci_set_power_state(dev, PCI_D3hot);
+ retval = pci_set_power_state(dev, d_state);
suspend_report_result(pci_set_power_state, retval);
if (retval == 0) {
int wake = device_can_wakeup(&hcd->self.root_hub->dev);

wake = wake && device_may_wakeup(hcd->self.controller);

- dev_dbg(hcd->self.controller, "--> PCI D3%s\n",
+ dev_dbg(hcd->self.controller, "--> PCI D%d%s\n",
+ d_state,
wake ? "/wakeup" : "");

/* Ignore these return values. We rely on pci code to
* reject requests the hardware can't implement, rather
* than coding the same thing.
*/
- (void) pci_enable_wake(dev, PCI_D3hot, wake);
+ (void) pci_enable_wake(dev, d_state, wake);
(void) pci_enable_wake(dev, PCI_D3cold, wake);
} else {
dev_dbg(&dev->dev, "PCI D3 suspend fail, %d\n",