From 5f9aea36b5ebf36e8391a0df03cc6f2d8d923a5d Mon Sep 17 00:00:00 2001 From: Hauke Mehrtens Date: Sat, 16 Nov 2019 13:14:21 +0100 Subject: backports: Add return value to backport_pci_disable_link_state() Since Linux upstream commit 4cfd21885592 ("PCI: let pci_disable_link_state propagate errors") The pci_disable_link_state() function can return an error. This return code is now used by the mt76 driver. In case it is not possible to disable ASPM, for example on some ACPI systems, we should return an error and mt76 handles this. Do this by checking the PCI registers if the operation was successfully. The checking of the PCI register was added by Felix Fietkau. Signed-off-by: Hauke Mehrtens --- backport/backport-include/linux/pci.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/backport/backport-include/linux/pci.h b/backport/backport-include/linux/pci.h index 84c4e8f6..1cc5f281 100644 --- a/backport/backport-include/linux/pci.h +++ b/backport/backport-include/linux/pci.h @@ -236,4 +236,29 @@ static inline struct pci_dev *pcie_find_root_port(struct pci_dev *dev) (PCI_IRQ_LEGACY | PCI_IRQ_MSI | PCI_IRQ_MSIX) #endif +#if defined(CONFIG_PCI) +#if LINUX_VERSION_IS_LESS(5,3,0) +static inline int +backport_pci_disable_link_state(struct pci_dev *pdev, int state) +{ + u16 aspmc; + + pci_disable_link_state(pdev, state); + + pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspmc); + if ((state & PCIE_LINK_STATE_L0S) && + (aspmc & PCI_EXP_LNKCTL_ASPM_L0S)) + return -EPERM; + + if ((state & PCIE_LINK_STATE_L1) && + (aspmc & PCI_EXP_LNKCTL_ASPM_L1)) + return -EPERM; + + return 0; +} +#define pci_disable_link_state LINUX_BACKPORT(pci_disable_link_state) + +#endif /* < 5.3 */ +#endif /* defined(CONFIG_PCI) */ + #endif /* _BACKPORT_LINUX_PCI_H */ -- cgit v1.2.3