Commit 575b98e3 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

PCI/ASPM: Add pcie_aspm_remove_cap() to override advertised link states 



Add pcie_aspm_remove_cap().  A quirk can use this to prevent use of ASPM
L0s or L1 link states, even if the device advertised support for them.

Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Tested-by: default avatarShawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: default avatarLukas Wunner <lukas@wunner.de>
Link: https://patch.msgid.link/20251110222929.2140564-3-helgaas@kernel.org
parent 4495bffd

drivers/pci/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -958,6 +958,7 @@ void pci_save_aspm_l1ss_state(struct pci_dev *dev); 
void pci_restore_aspm_l1ss_state(struct pci_dev *dev);



#ifdef CONFIG_PCIEASPM

void pcie_aspm_remove_cap(struct pci_dev *pdev, u32 lnkcap);

void pcie_aspm_init_link_state(struct pci_dev *pdev);

void pcie_aspm_exit_link_state(struct pci_dev *pdev);

void pcie_aspm_pm_state_change(struct pci_dev *pdev, bool locked);
@@ -965,6 +966,7 @@ void pcie_aspm_powersave_config_link(struct pci_dev *pdev); 
void pci_configure_ltr(struct pci_dev *pdev);

void pci_bridge_reconfigure_ltr(struct pci_dev *pdev);

#else

static inline void pcie_aspm_remove_cap(struct pci_dev *pdev, u32 lnkcap) { }

static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }

static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }

static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev, bool locked) { }

drivers/pci/pcie/aspm.c

+13 −0
Original line number Diff line number Diff line
@@ -1542,6 +1542,19 @@ int pci_enable_link_state_locked(struct pci_dev *pdev, int state) 
}

EXPORT_SYMBOL(pci_enable_link_state_locked);



void pcie_aspm_remove_cap(struct pci_dev *pdev, u32 lnkcap)

{

	if (lnkcap & PCI_EXP_LNKCAP_ASPM_L0S)

		pdev->aspm_l0s_support = 0;

	if (lnkcap & PCI_EXP_LNKCAP_ASPM_L1)

		pdev->aspm_l1_support = 0;



	pci_info(pdev, "ASPM: Link Capabilities%s%s treated as unsupported to avoid device defect\n",

		 lnkcap & PCI_EXP_LNKCAP_ASPM_L0S ? " L0s" : "",

		 lnkcap & PCI_EXP_LNKCAP_ASPM_L1 ? " L1" : "");



}



static int pcie_aspm_set_policy(const char *val,

				const struct kernel_param *kp)

{