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Commit 1ed276a7 authored by Lukas Wunner's avatar Lukas Wunner Committed by Bjorn Helgaas
Browse files

PCI: Autosense device removal in pci_bridge_d3_update() 



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: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarLukas Wunner <lukas@wunner.de>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 738a7edb

drivers/pci/bus.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/pci/pci.c

+5 −30
Original line number Diff line number Diff line
@@ -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);

drivers/pci/pci.h

+1 −2
Original line number Diff line number Diff line
@@ -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)

{

drivers/pci/remove.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}