[PATCH] PCI / hotplug: Propagate the "ignore hotplug" setting to parent

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Refine the mechanism introduced by commit f244d8b623da (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 (the 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
Reported-and-tested-by: tiagdtd-lava <tiagdtd-lava@yahoo.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

"Stable" material AFAICS.

---
 drivers/pci/pci.c   |   11 +++++++++++
 include/linux/pci.h |    6 +-----
 2 files changed, 12 insertions(+), 5 deletions(-)

Index: linux-pm/drivers/pci/pci.c
===================================================================
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -4319,6 +4319,17 @@ bool pci_device_is_present(struct pci_de
 }
 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);
Index: linux-pm/include/linux/pci.h
===================================================================
--- linux-pm.orig/include/linux/pci.h
+++ linux-pm/include/linux/pci.h
@@ -1002,6 +1002,7 @@ int __must_check pci_assign_resource(str
 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);
@@ -1039,11 +1040,6 @@ bool pci_dev_run_wake(struct pci_dev *de
 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)
 {