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-rw-r--r--drivers/pci/pcie/aspm.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 3b14d9e85dee..17ac1dce3286 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -351,12 +351,26 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
return;
}
+ /* Get upstream/downstream components' register state */
+ pcie_get_aspm_reg(parent, &upreg);
+ child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
+ pcie_get_aspm_reg(child, &dwreg);
+
+ /*
+ * If ASPM not supported, don't mess with the clocks and link,
+ * bail out now.
+ */
+ if (!(upreg.support & dwreg.support))
+ return;
+
/* Configure common clock before checking latencies */
pcie_aspm_configure_common_clock(link);
- /* Get upstream/downstream components' register state */
+ /*
+ * Re-read upstream/downstream components' register state
+ * after clock configuration
+ */
pcie_get_aspm_reg(parent, &upreg);
- child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
pcie_get_aspm_reg(child, &dwreg);
/*