[PATCH v1 2/4] PCI/ASPM: Use correct capability pointer to program LTR_L1.2_THRESHOLD

From: Bjorn Helgaas
Date: Mon Nov 13 2017 - 18:12:14 EST


From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Previously we programmed the LTR_L1.2_THRESHOLD in the parent (upstream)
device using the capability pointer of the *child* (downstream) device,
which corrupted some random word of the parent's config space.

Use the parent's L1 SS capability pointer to program its
LTR_L1.2_THRESHOLD.

Fixes: aeda9adebab8 ("PCI/ASPM: Configure L1 substate settings")
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx # v4.11+
CC: Rajat Jain <rajatja@xxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 46c59afb8355..a378dd9d2473 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -657,7 +657,7 @@ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
0xFF00, link->l1ss.ctl1);

/* Program LTR L1.2 threshold in both ports */
- pci_clear_and_set_dword(parent, dw_cap_ptr + PCI_L1SS_CTL1,
+ pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
0xE3FF0000, link->l1ss.ctl1);
pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
0xE3FF0000, link->l1ss.ctl1);