[PATCH] Revert "PCI/ASPM: Remove pcie_aspm_pm_state_change()"

Bjorn Helgaas
2024-01-02T23:26:05Z

From: Bjorn Helgaas <bhelgaas@google.com>

This reverts commit 08d0cc5f34265d1a1e3031f319f594bd1970976c.

Michael reported that when attempting to resume from suspend to RAM on ASUS
mini PC PN51-BB757MDE1 (DMI model: MINIPC PN51-E1), 08d0cc5f3426
("PCI/ASPM: Remove pcie_aspm_pm_state_change()") caused a 12-second delay
with no output, followed by a reboot.

Workarounds include:

- Reverting 08d0cc5f3426 ("PCI/ASPM: Remove pcie_aspm_pm_state_change()")
- Booting with "pcie_aspm=off"
- Booting with "pcie_aspm.policy=performance"
- "echo 0 | sudo tee /sys/bus/pci/devices/0000:03:00.0/link/l1_aspm"
before suspending
- Connecting a USB flash drive

Fixes: 08d0cc5f3426 ("PCI/ASPM: Remove pcie_aspm_pm_state_change()")
Reported-by: Michael Schaller <michael@5challer.de>
Link: https://lore.kernel.org/r/76c61361-b8b4-435f-a9f1-32b716763d62@5challer.de
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: <stable@vger.kernel.org>
---
drivers/pci/pci.c | 6 ++++++
drivers/pci/pci.h | 2 ++
drivers/pci/pcie/aspm.c | 19 +++++++++++++++++++
3 files changed, 27 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 55bc3576a985..bdbf8a94b4d0 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1335,6 +1335,9 @@ 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;
}

@@ -1429,6 +1432,9 @@ 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;
}

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 5ecbcf041179..f43873049d52 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -569,10 +569,12 @@ int pcie_retrain_link(struct pci_dev *pdev, bool use_lt);
#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

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 50b04ae5c394..8715e951c491 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1008,6 +1008,25 @@ 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;
--
2.34.1