[RFC][PATCH 2/10] PCI PM: Add suspend counterpart of pci_reenable_device
From: Rafael J. Wysocki
Date: Tue Dec 30 2008 - 17:50:50 EST
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@xxxxxxx>
---
drivers/pci/pci-driver.c | 35 ++++++++++++++++++++++++++++++-----
drivers/pci/pci.c | 36 ++++++++++++++++++++++++++++--------
drivers/pci/pci.h | 1 +
3 files changed, 59 insertions(+), 13 deletions(-)
Index: linux-2.6/drivers/pci/pci.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci.c
+++ linux-2.6/drivers/pci/pci.c
@@ -969,6 +969,32 @@ void pcim_pin_device(struct pci_dev *pde
*/
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
@@ -983,7 +1009,6 @@ void
pci_disable_device(struct pci_dev *dev)
{
struct pci_devres *dr;
- u16 pci_command;
dr = find_pci_dr(dev);
if (dr)
@@ -992,14 +1017,9 @@ 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;
}
/**
Index: linux-2.6/drivers/pci/pci.h
===================================================================
--- linux-2.6.orig/drivers/pci/pci.h
+++ linux-2.6/drivers/pci/pci.h
@@ -40,6 +40,7 @@ struct pci_platform_pm_ops {
};
extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
+extern void pci_disable_enabled_device(struct pci_dev *dev);
extern void pci_pm_init(struct pci_dev *dev);
extern void pci_allocate_cap_save_buffers(struct pci_dev *dev);
Index: linux-2.6/drivers/pci/pci-driver.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci-driver.c
+++ linux-2.6/drivers/pci/pci-driver.c
@@ -310,9 +310,19 @@ static bool pci_has_legacy_pm_support(st
/*
* Default "suspend" method for devices that have no driver provided suspend,
- * or not even a driver at all.
+ * or not even a driver at all (first part).
+ */
+static void pci_default_pm_suspend_early(struct pci_dev *pci_dev)
+{
+ /* If device is enabled at this point, disable it */
+ pci_disable_enabled_device(pci_dev);
+}
+
+/*
+ * Default "suspend" method for devices that have no driver provided suspend,
+ * or not even a driver at all (second part).
*/
-static void pci_default_pm_suspend(struct pci_dev *pci_dev)
+static void pci_default_pm_suspend_late(struct pci_dev *pci_dev)
{
pci_save_state(pci_dev);
/*
@@ -363,7 +373,11 @@ static int pci_legacy_suspend(struct dev
i = drv->suspend(pci_dev, state);
suspend_report_result(drv->suspend, i);
} else {
- pci_default_pm_suspend(pci_dev);
+ /*
+ * For compatibility with existing code with legacy PM support
+ * don't call pci_default_pm_suspend_early() here.
+ */
+ pci_default_pm_suspend_late(pci_dev);
}
return i;
}
@@ -441,7 +455,10 @@ static int pci_pm_suspend(struct device
}
} else if (pci_has_legacy_pm_support(pci_dev)) {
error = pci_legacy_suspend(dev, PMSG_SUSPEND);
+ } else {
+ pci_default_pm_suspend_early(pci_dev);
}
+
pci_fixup_device(pci_fixup_suspend, pci_dev);
return error;
@@ -461,7 +478,7 @@ static int pci_pm_suspend_noirq(struct d
} else if (pci_has_legacy_pm_support(pci_dev)) {
error = pci_legacy_suspend_late(dev, PMSG_SUSPEND);
} else {
- pci_default_pm_suspend(pci_dev);
+ pci_default_pm_suspend_late(pci_dev);
}
return error;
@@ -532,6 +549,8 @@ static int pci_pm_freeze(struct device *
} else if (pci_has_legacy_pm_support(pci_dev)) {
error = pci_legacy_suspend(dev, PMSG_FREEZE);
pci_fixup_device(pci_fixup_suspend, pci_dev);
+ } else {
+ pci_default_pm_suspend_early(pci_dev);
}
return error;
@@ -551,7 +570,7 @@ static int pci_pm_freeze_noirq(struct de
} else if (pci_has_legacy_pm_support(pci_dev)) {
error = pci_legacy_suspend_late(dev, PMSG_FREEZE);
} else {
- pci_default_pm_suspend(pci_dev);
+ pci_default_pm_suspend_late(pci_dev);
}
return error;
@@ -569,6 +588,8 @@ static int pci_pm_thaw(struct device *de
} else if (pci_has_legacy_pm_support(pci_dev)) {
pci_fixup_device(pci_fixup_resume, pci_dev);
error = pci_legacy_resume(dev);
+ } else {
+ pci_default_pm_resume_late(pci_dev);
}
return error;
@@ -586,6 +607,8 @@ static int pci_pm_thaw_noirq(struct devi
} else if (pci_has_legacy_pm_support(pci_dev)) {
pci_fixup_device(pci_fixup_resume_early, to_pci_dev(dev));
error = pci_legacy_resume_early(dev);
+ } else {
+ pci_default_pm_resume_early(pci_dev);
}
return error;
@@ -604,6 +627,8 @@ static int pci_pm_poweroff(struct device
}
} else if (pci_has_legacy_pm_support(pci_dev)) {
error = pci_legacy_suspend(dev, PMSG_HIBERNATE);
+ } else {
+ pci_default_pm_suspend_early(pci_dev);
}
pci_fixup_device(pci_fixup_suspend, pci_dev);
--
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