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-rw-r--r--drivers/acpi/pci_root.c6
-rw-r--r--drivers/pci/probe.c5
-rw-r--r--include/linux/acpi.h3
-rw-r--r--include/linux/pci.h1
4 files changed, 14 insertions, 1 deletions
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 0da18bde6a16..2ff0d6702a2e 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -153,6 +153,7 @@ static struct pci_osc_bit_struct pci_osc_control_bit[] = {
{ OSC_PCI_EXPRESS_PME_CONTROL, "PME" },
{ OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
{ OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
+ { OSC_PCI_EXPRESS_LTR_CONTROL, "LTR" },
};
static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
@@ -475,6 +476,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
| OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
| OSC_PCI_EXPRESS_PME_CONTROL;
+ if (IS_ENABLED(CONFIG_PCIEASPM))
+ control |= OSC_PCI_EXPRESS_LTR_CONTROL;
+
if (pci_aer_available()) {
if (aer_acpi_firmware_first())
dev_info(&device->dev,
@@ -905,6 +909,8 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
host_bridge->native_aer = 0;
if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL))
host_bridge->native_pme = 0;
+ if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
+ host_bridge->native_ltr = 0;
pci_scan_child_bus(bus);
pci_set_host_bridge_release(host_bridge, acpi_pci_root_release_info,
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ac91b6fd0bcd..cc1688d75664 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -554,6 +554,7 @@ struct pci_host_bridge *pci_alloc_host_bridge(size_t priv)
bridge->native_aer = 1;
bridge->native_hotplug = 1;
bridge->native_pme = 1;
+ bridge->native_ltr = 1;
return bridge;
}
@@ -1954,9 +1955,13 @@ static void pci_configure_relaxed_ordering(struct pci_dev *dev)
static void pci_configure_ltr(struct pci_dev *dev)
{
#ifdef CONFIG_PCIEASPM
+ struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
u32 cap;
struct pci_dev *bridge;
+ if (!host->native_ltr)
+ return;
+
if (!pci_is_pcie(dev))
return;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 15bfb15c2fa5..49f63c67a9d1 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -506,7 +506,8 @@ extern bool osc_pc_lpi_support_confirmed;
#define OSC_PCI_EXPRESS_PME_CONTROL 0x00000004
#define OSC_PCI_EXPRESS_AER_CONTROL 0x00000008
#define OSC_PCI_EXPRESS_CAPABILITY_CONTROL 0x00000010
-#define OSC_PCI_CONTROL_MASKS 0x0000001f
+#define OSC_PCI_EXPRESS_LTR_CONTROL 0x00000020
+#define OSC_PCI_CONTROL_MASKS 0x0000003f
#define ACPI_GSB_ACCESS_ATTRIB_QUICK 0x00000002
#define ACPI_GSB_ACCESS_ATTRIB_SEND_RCV 0x00000004
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 73178a2fcee0..d0149c01996d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -473,6 +473,7 @@ struct pci_host_bridge {
unsigned int native_aer:1; /* OS may use PCIe AER */
unsigned int native_hotplug:1; /* OS may use PCIe hotplug */
unsigned int native_pme:1; /* OS may use PCIe PME */
+ unsigned int native_ltr:1; /* OS may use PCIe LTR */
/* Resource alignment requirements */
resource_size_t (*align_resource)(struct pci_dev *dev,
const struct resource *res,