According to "PCIe r6.0, sec 5.5.4", add note about D0 requirement in
pci_enable_link_state() kernel-doc.
Signed-off-by: Jian-Hong Pan <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Kuppuswamy Sathyanarayanan <[email protected]>
---
v3:
- Fix as readable comments
v4:
- The same
v5:
- Tweak and simplify the commit message
drivers/pci/pcie/aspm.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 2428d278e015..91a8b35b1ae2 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1446,6 +1446,9 @@ static int __pci_enable_link_state(struct pci_dev *pdev, int state, bool locked)
* touch the LNKCTL register. Also note that this does not enable states
* disabled by pci_disable_link_state(). Return 0 or a negative errno.
*
+ * Note: Ensure devices are in D0 before enabling PCI-PM L1 PM Substates, per
+ * PCIe r6.0, sec 5.5.4.
+ *
* @pdev: PCI device
* @state: Mask of ASPM link states to enable
*/
@@ -1462,6 +1465,9 @@ EXPORT_SYMBOL(pci_enable_link_state);
* can't touch the LNKCTL register. Also note that this does not enable states
* disabled by pci_disable_link_state(). Return 0 or a negative errno.
*
+ * Note: Ensure devices are in D0 before enabling PCI-PM L1 PM Substates, per
+ * PCIe r6.0, sec 5.5.4.
+ *
* @pdev: PCI device
* @state: Mask of ASPM link states to enable
*
--
2.44.0