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authorRafael J. Wysocki <rjw@sisk.pl>2011-03-05 21:48:44 +0100
committerJesse Barnes <jbarnes@virtuousgeek.org>2011-05-10 15:43:29 -0700
commit83d74e036b94ffbf871667eede5ef02993709452 (patch)
tree69ef4a3bc6ed289389ab6221df46459e088e4d11 /drivers/pci
parent3504e47ffca5ed3f9e2cc7d37b428fbf1e00ad1b (diff)
downloadop-kernel-dev-83d74e036b94ffbf871667eede5ef02993709452.zip
op-kernel-dev-83d74e036b94ffbf871667eede5ef02993709452.tar.gz
PCI/PM: Add kerneldoc description of pci_pm_reset()
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> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 2472e71..44d1c7c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2479,6 +2479,21 @@ 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;
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