Thread (2 messages) 2 messages, 2 authors, 2018-02-28

[PATCH V2] PCI/ASPM: Suppress common clock mode setting failure

From: helgaas@kernel.org (Bjorn Helgaas)
Date: 2018-02-28 21:24:17
Also in: linux-arm-msm, linux-pci, lkml

On Mon, Jan 22, 2018 at 03:12:01PM -0500, Sinan Kaya wrote:
Code is emitting warnings when it tries to set the common clock mode for
ASPM and ASPM is already configured to common clock mode by the UEFI BIOS.
Let's bail out silently in such a case.

pci 0004:00:00.0: ASPM: Could not configure common clock

Signed-off-by: Sinan Kaya <redacted>
Applied to pci/aspm for v4.17, thanks!
quoted hunk ↗ jump to hunk
---
 drivers/pci/pcie/aspm.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 9783e10..913b90d 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -240,6 +240,24 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
 	if (!(reg16 & PCI_EXP_LNKSTA_SLC))
 		same_clock = 0;
 
+	/* Port might be already in common clock mode */
+	pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
+	if (same_clock && (reg16 & PCI_EXP_LNKCTL_CCC)) {
+		bool consistent = true;
+
+		list_for_each_entry(child, &linkbus->devices, bus_list) {
+			pcie_capability_read_word(child, PCI_EXP_LNKCTL,
+						  &reg16);
+			if (!(reg16 & PCI_EXP_LNKCTL_CCC)) {
+				consistent = false;
+				break;
+			}
+		}
+		if (consistent)
+			return;
+		dev_warn(&parent->dev, "ASPM: current common clock configuration is broken, reconfiguring\n");
+	}
+
 	/* Configure downstream component, all functions */
 	list_for_each_entry(child, &linkbus->devices, bus_list) {
 		pcie_capability_read_word(child, PCI_EXP_LNKCTL, &reg16);
-- 
1.9.1


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