[PATCH 2/4] PCI: Fix runtime PM usage count underflow

[Mario Limonciello <superm1@kernel.org>]

From: Mario Limonciello <mario.limonciello@amd.com>

When a USB4 dock is unplugged the PCIe bridge it's connected to will
remove issue a "Link Down" and "Card not detected event". The PCI core
will treat this as a surprise hotplug event and unconfigure all downstream
devices. This involves setting the device error state to
`pci_channel_io_perm_failure`.

When PCI core gets to the point that the device is removed using
pci_device_remove() the runtime count has already been decremented and
so calling pm_runtime_put_sync() will cause an underflow.

Detect the device is in the error state and skip the call for this cleanup
path.

Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
 drivers/pci/pci-driver.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 9f6e145d93d62..ab4cfdfc8fbc0 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -479,7 +479,8 @@ static void pci_device_remove(struct device *dev)
 	pci_iov_remove(pci_dev);
 
 	/* Undo the runtime PM settings in local_pci_probe() */
-	pm_runtime_put_sync(dev);
+	if (pci_dev->error_state != pci_channel_io_perm_failure)
+		pm_runtime_put_sync(dev);
 
 	/*
 	 * If the device is still on, set the power state as "unknown",
-- 
2.43.0