diff options
Diffstat (limited to 'drivers/pci/pci.c')
| -rw-r--r-- | drivers/pci/pci.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e55d944ff30f..3d98834ccc3a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1477,6 +1477,24 @@ static int pci_save_pcie_state(struct pci_dev *dev) return 0; } +void pci_bridge_reconfigure_ltr(struct pci_dev *dev) +{ +#ifdef CONFIG_PCIEASPM + struct pci_dev *bridge; + u32 ctl; + + bridge = pci_upstream_bridge(dev); + if (bridge && bridge->ltr_path) { + pcie_capability_read_dword(bridge, PCI_EXP_DEVCTL2, &ctl); + if (!(ctl & PCI_EXP_DEVCTL2_LTR_EN)) { + pci_dbg(bridge, "re-enabling LTR\n"); + pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2, + PCI_EXP_DEVCTL2_LTR_EN); + } + } +#endif +} + static void pci_restore_pcie_state(struct pci_dev *dev) { int i = 0; @@ -1487,6 +1505,13 @@ static void pci_restore_pcie_state(struct pci_dev *dev) if (!save_state) return; + /* + * Downstream ports reset the LTR enable bit when link goes down. + * Check and re-configure the bit here before restoring device. + * PCIe r5.0, sec 7.5.3.16. + */ + pci_bridge_reconfigure_ltr(dev); + cap = (u16 *)&save_state->cap.data[0]; pcie_capability_write_word(dev, PCI_EXP_DEVCTL, cap[i++]); pcie_capability_write_word(dev, PCI_EXP_LNKCTL, cap[i++]); |