Commit 08d0cc5f authored by Kai-Heng Feng's avatar Kai-Heng Feng Committed by Bjorn Helgaas
Browse files

PCI/ASPM: Remove pcie_aspm_pm_state_change() 

pcie_aspm_pm_state_change() was introduced at the inception of PCIe ASPM
code, but it can cause some issues. For instance, when ASPM config is
changed via sysfs, those changes won't persist across power state change
because pcie_aspm_pm_state_change() overwrites them.

Also, if the driver restores L1SS [1] after system resume, the restored
state will also be overwritten by pcie_aspm_pm_state_change().

Remove pcie_aspm_pm_state_change().  If there's any hardware that really
needs it to function, a quirk can be used instead.

[1] https://lore.kernel.org/linux-pci/20220201123536.12962-1-vidyas@nvidia.com/
Link: https://lore.kernel.org/r/20220509073639.2048236-1-kai.heng.feng@canonical.com


[bhelgaas: remove additional pcie_aspm_pm_state_change() call in
pci_set_low_power_state(), added by
10aa5377 ("PCI/PM: Split pci_raw_set_power_state()") and moved by
7957d201 ("PCI/PM: Relocate pci_set_low_power_state()")]
Signed-off-by: default avatarKai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent f2906aa8

drivers/pci/pci.c

+0 −6
Original line number Diff line number Diff line
@@ -1293,9 +1293,6 @@ static int pci_set_full_power_state(struct pci_dev *dev) 
		pci_restore_bars(dev);

	}



	if (dev->bus->self)

		pcie_aspm_pm_state_change(dev->bus->self);



	return 0;

}
@@ -1390,9 +1387,6 @@ static int pci_set_low_power_state(struct pci_dev *dev, pci_power_t state) 
				     pci_power_name(dev->current_state),

				     pci_power_name(state));



	if (dev->bus->self)

		pcie_aspm_pm_state_change(dev->bus->self);



	return 0;

}

drivers/pci/pci.h

+0 −2
Original line number Diff line number Diff line
@@ -560,12 +560,10 @@ bool pcie_wait_for_link(struct pci_dev *pdev, bool active); 
#ifdef CONFIG_PCIEASPM

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);

void pcie_aspm_powersave_config_link(struct pci_dev *pdev);

#else

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) { }

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

#endif

drivers/pci/pcie/aspm.c

+0 −19
Original line number Diff line number Diff line
@@ -1012,25 +1012,6 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev) 
	up_read(&pci_bus_sem);

}



/* @pdev: the root port or switch downstream port */

void pcie_aspm_pm_state_change(struct pci_dev *pdev)

{

	struct pcie_link_state *link = pdev->link_state;



	if (aspm_disabled || !link)

		return;

	/*

	 * Devices changed PM state, we should recheck if latency

	 * meets all functions' requirement

	 */

	down_read(&pci_bus_sem);

	mutex_lock(&aspm_lock);

	pcie_update_aspm_capable(link->root);

	pcie_config_aspm_path(link);

	mutex_unlock(&aspm_lock);

	up_read(&pci_bus_sem);

}



void pcie_aspm_powersave_config_link(struct pci_dev *pdev)

{

	struct pcie_link_state *link = pdev->link_state;