PCI PM: Add suspend counterpart of pci_reenable_device

PCI devices without drivers are not disabled during suspend and
hibernation, but they are enabled during resume, with the help of
pci_reenable_device(), so there is an unbalanced execution of
pcibios_enable_device() in the resume code path.

To correct this introduce function pci_disable_enabled_device()
that will disable the argument device, if it is enabled when the
function is being run, without updating the device's pci_dev
structure and use it in the suspend code path to balance the
pci_reenable_device() executed during resume.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 28 insertions, 8 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f3fd55df67db..6e309c8b47df 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -970,6 +970,32 @@ void pcim_pin_device(struct pci_dev *pdev)
  */
 void __attribute__ ((weak)) pcibios_disable_device (struct pci_dev *dev) {}
 
+static void do_pci_disable_device(struct pci_dev *dev)
+{
+        u16 pci_command;
+
+        pci_read_config_word(dev, PCI_COMMAND, &pci_command);
+        if (pci_command & PCI_COMMAND_MASTER) {
+                pci_command &= ~PCI_COMMAND_MASTER;
+                pci_write_config_word(dev, PCI_COMMAND, pci_command);
+        }
+
+        pcibios_disable_device(dev);
+}
+
+/**
+ * pci_disable_enabled_device - Disable device without updating enable_cnt
+ * @dev: PCI device to disable
+ *
+ * NOTE: This function is a backend of PCI power management routines and is
+ * not supposed to be called drivers.
+ */
+void pci_disable_enabled_device(struct pci_dev *dev)
+{
+        if (atomic_read(&dev->enable_cnt))
+                do_pci_disable_device(dev);
+}
+
 /**
  * pci_disable_device - Disable PCI device after use
  * @dev: PCI device to be disabled
@@ -984,7 +1010,6 @@ void
 pci_disable_device(struct pci_dev *dev)
 {
         struct pci_devres *dr;
-        u16 pci_command;
 
         dr = find_pci_dr(dev);
         if (dr)
@@ -993,14 +1018,9 @@ pci_disable_device(struct pci_dev *dev)
         if (atomic_sub_return(1, &dev->enable_cnt) != 0)
                 return;
 
-        pci_read_config_word(dev, PCI_COMMAND, &pci_command);
-        if (pci_command & PCI_COMMAND_MASTER) {
-                pci_command &= ~PCI_COMMAND_MASTER;
-                pci_write_config_word(dev, PCI_COMMAND, pci_command);
-        }
-        dev->is_busmaster = 0;
+        do_pci_disable_device(dev);
 
-        pcibios_disable_device(dev);
+        dev->is_busmaster = 0;
 }
 
 /**