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PCI: Autosense device removal in pci_bridge_d3_update()

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The algorithm to update the flag indicating whether a bridge may go to D3
makes a few optimizations based on whether the update was caused by the
removal of a device on the one hand, versus the addition of a device or the
change of its D3cold flags on the other hand.

The information whether the update pertains to a removal is currently
passed in by the caller, but the function may as well determine that itself
by examining the device in question, thereby allowing for a considerable
simplification and reduction of the code.

Out of several options to determine removal, I've chosen the function
device_is_registered() because it's cheap:  It merely returns the
dev->kobj.state_in_sysfs flag.  That flag is set through device_add() when
the root bus is scanned and cleared through device_remove().  The call to
pci_bridge_d3_update() happens after each of these calls, respectively, so
the ordering is correct.

No functional change intended.

Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Lukas Wunner 2016-10-28 10:52:06 +02:00 committed by Bjorn Helgaas
parent 738a7edbfc
commit 1ed276a7b9
4 changed files with 8 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/pci/bus.c
View File

@ -320,7 +320,7 @@ void pci_bus_add_device(struct pci_dev *dev)
pci_fixup_device(pci_fixup_final, dev);
pci_create_sysfs_dev_files(dev);
pci_proc_attach_device(dev);
pci_bridge_d3_device_changed(dev);
pci_bridge_d3_update(dev);
dev->match_driver = true;
retval = device_attach(&dev->dev);

35
drivers/pci/pci.c
View File

@ -2281,14 +2281,14 @@ static int pci_dev_check_d3cold(struct pci_dev *dev, void *data)
/*
* pci_bridge_d3_update - Update bridge D3 capabilities
* @dev: PCI device which is changed
* @remove: Is the device being removed
*
* Update upstream bridge PM capabilities accordingly depending on if the
* device PM configuration was changed or the device is being removed. The
* change is also propagated upstream.
*/
static void pci_bridge_d3_update(struct pci_dev *dev, bool remove)
void pci_bridge_d3_update(struct pci_dev *dev)
{
bool remove = !device_is_registered(&dev->dev);
struct pci_dev *bridge;
bool d3cold_ok = true;
@ -2315,35 +2315,10 @@ static void pci_bridge_d3_update(struct pci_dev *dev, bool remove)
if (bridge->bridge_d3 != d3cold_ok) {
bridge->bridge_d3 = d3cold_ok;
/* Propagate change to upstream bridges */
pci_bridge_d3_update(bridge, false);
pci_bridge_d3_update(bridge);
}
}
/**
* pci_bridge_d3_device_changed - Update bridge D3 capabilities on change
* @dev: PCI device that was changed
*
* If a device is added or its PM configuration, such as is it allowed to
* enter D3cold, is changed this function updates upstream bridge PM
* capabilities accordingly.
*/
void pci_bridge_d3_device_changed(struct pci_dev *dev)
{
pci_bridge_d3_update(dev, false);
}
/**
* pci_bridge_d3_device_removed - Update bridge D3 capabilities on remove
* @dev: PCI device being removed
*
* Function updates upstream bridge PM capabilities based on other devices
* still left on the bus.
*/
void pci_bridge_d3_device_removed(struct pci_dev *dev)
{
pci_bridge_d3_update(dev, true);
}
/**
* pci_d3cold_enable - Enable D3cold for device
* @dev: PCI device to handle
@ -2356,7 +2331,7 @@ void pci_d3cold_enable(struct pci_dev *dev)
{
if (dev->no_d3cold) {
dev->no_d3cold = false;
pci_bridge_d3_device_changed(dev);
pci_bridge_d3_update(dev);
}
}
EXPORT_SYMBOL_GPL(pci_d3cold_enable);
@ -2373,7 +2348,7 @@ void pci_d3cold_disable(struct pci_dev *dev)
{
if (!dev->no_d3cold) {
dev->no_d3cold = true;
pci_bridge_d3_device_changed(dev);
pci_bridge_d3_update(dev);
}
}
EXPORT_SYMBOL_GPL(pci_d3cold_disable);

3
drivers/pci/pci.h
View File

@ -85,8 +85,7 @@ void pci_pm_init(struct pci_dev *dev);
void pci_ea_init(struct pci_dev *dev);
void pci_allocate_cap_save_buffers(struct pci_dev *dev);
void pci_free_cap_save_buffers(struct pci_dev *dev);
void pci_bridge_d3_device_changed(struct pci_dev *dev);
void pci_bridge_d3_device_removed(struct pci_dev *dev);
void pci_bridge_d3_update(struct pci_dev *dev);
static inline void pci_wakeup_event(struct pci_dev *dev)
{

2
drivers/pci/remove.c
View File

@ -40,7 +40,7 @@ static void pci_destroy_dev(struct pci_dev *dev)
list_del(&dev->bus_list);
up_write(&pci_bus_sem);
pci_bridge_d3_device_removed(dev);
pci_bridge_d3_update(dev);
pci_free_resources(dev);
put_device(&dev->dev);
}