[PATCH v3 2/2] PCI: Fix runtime PM usage count underflow on device unplug

[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.

pci_stop_bus_device() will call device_release_driver(). As part of device
release sequence pm_runtime_put_sync() is called for the device which will
decrement the runtime counter to 0. After this, the device remove callback
(pci_device_remove()) will be called which again calls pm_runtime_put_sync()
but as the counter is already 0 will cause an underflow.

This behavior was introduced in commit 967577b062417 ("PCI/PM: Keep runtime
PM enabled for unbound PCI devices") to prevent asymmetrical get/put from
probe/remove, but this misses out on the point that when releasing a driver
the usage count is decremented from the device core.

Drop the extra call from pci_device_remove().

Fixes: 967577b062417 ("PCI/PM: Keep runtime PM enabled for unbound PCI devices")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
v3:
 * git archeaology
 * Drop call alltogether, not just for the device disconnected case
v2:
 * Use pci_dev_is_disconnected()
v1: https://lore.kernel.org/linux-usb/20250609020223.269407-1-superm1@kernel.org/T/#mf95c947990d016fbfccfd11afe60b8ae08aafa0b
---
 drivers/pci/pci-driver.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index b78b98133e7df..63f1cb11906ad 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -478,9 +478,6 @@ static void pci_device_remove(struct device *dev)
 	pci_dev->driver = NULL;
 	pci_iov_remove(pci_dev);
 
-	/* Undo the runtime PM settings in local_pci_probe() */
-	pm_runtime_put_sync(dev);
-
 	/*
 	 * If the device is still on, set the power state as "unknown",
 	 * since it might change by the next time we load the driver.
-- 
2.43.0