PCI: Propagate the "ignore hotplug" setting to parent

Refine the mechanism introduced by commit f244d8b ("ACPIPHP / radeon /
nouveau: Fix VGA switcheroo problem related to hotplug") to propagate the
ignore_hotplug setting of the device to its parent bridge in case hotplug
notifications related to the graphics adapter switching are given for the
bridge rather than for the device itself (they need to be ignored in both
cases).

Link: https://bugzilla.kernel.org/show_bug.cgi?id=61891
Link: https://bugs.freedesktop.org/show_bug.cgi?id=88927
Fixes: b440bde ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device")
Reported-and-tested-by: tiagdtd-lava <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
CC: [email protected]	# v3.17+

Author: rafaeljw

drivers/pci/pci.c

@@ -4324,6 +4324,17 @@ bool pci_device_is_present(struct pci_dev *pdev)
 }
 EXPORT_SYMBOL_GPL(pci_device_is_present);
 
+void pci_ignore_hotplug(struct pci_dev *dev)
+{
+	struct pci_dev *bridge = dev->bus->self;
+
+	dev->ignore_hotplug = 1;
+	/* Propagate the "ignore hotplug" setting to the parent bridge. */
+	if (bridge)
+		bridge->ignore_hotplug = 1;
+}
+EXPORT_SYMBOL_GPL(pci_ignore_hotplug);
+
 #define RESOURCE_ALIGNMENT_PARAM_SIZE COMMAND_LINE_SIZE
 static char resource_alignment_param[RESOURCE_ALIGNMENT_PARAM_SIZE] = {0};
 static DEFINE_SPINLOCK(resource_alignment_lock);

include/linux/pci.h

@@ -1006,6 +1006,7 @@ int __must_check pci_assign_resource(struct pci_dev *dev, int i);
 int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);
 int pci_select_bars(struct pci_dev *dev, unsigned long flags);
 bool pci_device_is_present(struct pci_dev *pdev);
+void pci_ignore_hotplug(struct pci_dev *dev);
 
 /* ROM control related routines */
 int pci_enable_rom(struct pci_dev *pdev);
@@ -1043,11 +1044,6 @@ bool pci_dev_run_wake(struct pci_dev *dev);
 bool pci_check_pme_status(struct pci_dev *dev);
 void pci_pme_wakeup_bus(struct pci_bus *bus);
 
-static inline void pci_ignore_hotplug(struct pci_dev *dev)
-{
-	dev->ignore_hotplug = 1;
-}
-
 static inline int pci_enable_wake(struct pci_dev *dev, pci_power_t state,
 				  bool enable)
 {