From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
187f91db8237 ("PCI/ASPM: Remove struct aspm_register_info.l1ss_cap")
inadvertently removed a check for existence of the L1 PM Substates (L1SS)
Capability before reading it.
If there is no L1SS Capability, this means we mistakenly read PCI_COMMAND
and PCI_STATUS (config address 0x04) and interpret that as the PCI_L1SS_CAP
register, so we may incorrectly configure L1SS.
Make sure the L1SS Capability exists before trying to read it.
Fixes: 187f91db8237 ("PCI/ASPM: Remove struct aspm_register_info.l1ss_cap")
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 4535228e4a64..f12d117f44e0 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -560,6 +560,9 @@ static void aspm_l1ss_init(struct pcie_link_state *link)
u32 parent_l1ss_cap, child_l1ss_cap;
u32 parent_l1ss_ctl1 = 0, child_l1ss_ctl1 = 0;
+ if (!parent->l1ss || !child->l1ss)
+ return;
+
/* Setup L1 substate */
pci_read_config_dword(parent, parent->l1ss + PCI_L1SS_CAP,
&parent_l1ss_cap);
--
2.25.1
