[PATCH 4.14 031/193] PCI/ASPM: Use correct capability pointer to program LTR_L1.2_THRESHOLD

From: Greg Kroah-Hartman
Date: Tue Nov 28 2017 - 05:43:28 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

commit c00054f540bf81e592e1fee709b0bdbf20f478b5 upstream.

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>
Reviewed-by: Vidya Sagar <vidyas@xxxxxxxxxx>
CC: Rajat Jain <rajatja@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/pci/pcie/aspm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -658,7 +658,7 @@ static void pcie_config_aspm_l1ss(struct
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);