diff mbox

[v2] PCI / PM: Add kerneldoc description of pci_pm_reset()

Message ID 201103052148.44413.rjw@sisk.pl (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Rafael Wysocki March 5, 2011, 8:48 p.m. UTC 
None

Comments

Jesse Barnes April 8, 2011, 7:50 p.m. UTC | #1 
On Sat, 5 Mar 2011 21:48:44 +0100
"Rafael J. Wysocki" <rjw@sisk.pl> wrote:

> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> The pci_pm_reset() function is not a very nice interface due to its
> limitations and conditional behavior (e.g. it doesn't affect devices
> in low-power states), but it cannot be simply dropped, because
> existing device drivers may depend on it.  However, its behavior and
> limitations should be well documented, so add an appropriate
> kerneldoc comment to it.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
> ---

Applied to linux-next, thanks.
diff mbox

Patch

Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -2473,6 +2473,21 @@  clear:
 	return 0;
 }
 
+/**
+ * pci_pm_reset - Put device into PCI_D3 and back into PCI_D0.
+ * @dev: Device to reset.
+ * @probe: If set, only check if the device can be reset this way.
+ *
+ * If @dev supports native PCI PM and its PCI_PM_CTRL_NO_SOFT_RESET flag is
+ * unset, it will be reinitialized internally when going from PCI_D3hot to
+ * PCI_D0.  If that's the case and the device is not in a low-power state
+ * already, force it into PCI_D3hot and back to PCI_D0, causing it to be reset.
+ *
+ * NOTE: This causes the caller to sleep for twice the device power transition
+ * cooldown period, which for the D0->D3hot and D3hot->D0 transitions is 10 ms
+ * by devault (i.e. unless the @dev's d3_delay field has a different value).
+ * Moreover, only devices in D0 can be reset by this function.
+ */
 static int pci_pm_reset(struct pci_dev *dev, int probe)
 {
 	u16 csr;