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SubjectRe: [linux-pm] Adapt drivers to type-safe pci
Date
On Monday 01 November 2004 12:26, Pavel Machek wrote:
> Hi!
>
> This adapts few drivers to type-safe pci powermanagment. I introduced
> device_to_pci_state helper that will be usefull to few drivers... Does
> it look okay?

I'd rather have something like the attached patch.
Fixed policy mappings are generically broken; what
about devices that don't support PCI_D2?

This should I guess use the new "pci_power_t", but
I'm not that current yet.

- Dave
--- 1.73/drivers/pci/pci.c 2004-10-06 09:42:55 -07:00
+++ edited/drivers/pci/pci.c 2004-11-01 16:55:48 -08:00
@@ -229,7 +229,7 @@
/**
* pci_set_power_state - Set the power state of a PCI device
* @dev: PCI device to be suspended
- * @state: Power state we're entering
+ * @state: PCI power state (D0, D1, D2, D3hot, D3cold) we're entering
*
* Transition a device to a new power state, using the Power Management
* Capabilities in the device's config space.
@@ -298,6 +298,54 @@

return 0;
}
+
+/**
+ * pci_choose_state - Choose the power state of a PCI device
+ * @dev: PCI device to be suspended
+ * @state: target sleep state for the whole system
+ *
+ * If the device doesn't support PCI power management, this does nothing.
+ * Otherwise it puts the device in a PCI power state that it supports,
+ * and which for most devices is appropriate to that system sleep state.
+ * Some drivers will need to choose the PCI state themselves, calling
+ * pci_set_power_state() directly.
+ */
+void
+pci_choose_state(struct pci_dev *pdev, suspend_state_t sleepstate)
+{
+ int pm, state;
+ u16 pmc;
+
+ /* nothing to do for legacy PCI devices */
+ pm = pci_find_capability(pdev, PCI_CAP_ID_PM);
+ if (!pm)
+ return;
+
+ /* map to a PCI PM state this device supports
+ * FIXME ACPI may know what states to use; we should probably
+ * prefer that policy to this one.
+ */
+ state = 3;
+ switch (sleepstate) {
+ case PM_SUSPEND_ON:
+ state = 0;
+ break;
+ case PM_SUSPEND_STANDBY:
+ case PM_SUSPEND_MEM:
+ pci_read_config_word(pdev, pm + PCI_PM_PMC, &pmc);
+ if (sleepstate == PM_SUSPEND_STANDBY
+ && (pmc & PCI_PM_CAP_D1) != 0)
+ state = 1;
+ else if ((pmc & PCI_PM_CAP_D2) != 0)
+ state = 2;
+ break;
+ }
+
+ /* maybe go to a deeper power state */
+ if (pdev->current_state < state)
+ pci_set_power_state(pdev, state);
+}
+EXPORT_SYMBOL(pci_choose_state);

/**
* pci_save_state - save the PCI configuration space of a device before suspending
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