2005-04-16 16:20:36 -06:00
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#include <linux/pci.h>
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#include <linux/module.h>
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PCI: add PCI Express ASPM support
PCI Express ASPM defines a protocol for PCI Express components in the D0
state to reduce Link power by placing their Links into a low power state
and instructing the other end of the Link to do likewise. This
capability allows hardware-autonomous, dynamic Link power reduction
beyond what is achievable by software-only controlled power management.
However, The device should be configured by software appropriately.
Enabling ASPM will save power, but will introduce device latency.
This patch adds ASPM support in Linux. It introduces a global policy for
ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control
it. The interface can be used as a boot option too. Currently we have
below setting:
-default, BIOS default setting
-powersave, highest power saving mode, enable all available ASPM
state and clock power management
-performance, highest performance, disable ASPM and clock power
management
By default, the 'default' policy is used currently.
In my test, power difference between powersave mode and performance mode
is about 1.3w in a system with 3 PCIE links.
Note: some devices might not work well with aspm, either because chipset
issue or device issue. The patch provide API (pci_disable_link_state),
driver can disable ASPM for specific device.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-24 18:46:41 -07:00
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#include <linux/pci-aspm.h>
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2005-04-16 16:20:36 -06:00
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#include "pci.h"
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2014-02-01 07:38:29 -07:00
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static void pci_free_resources(struct pci_dev *dev)
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{
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int i;
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pci_cleanup_rom(dev);
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for (i = 0; i < PCI_NUM_RESOURCES; i++) {
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struct resource *res = dev->resource + i;
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if (res->parent)
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release_resource(res);
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}
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}
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2006-09-12 11:16:36 -06:00
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static void pci_stop_dev(struct pci_dev *dev)
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2005-04-16 16:20:36 -06:00
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{
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2013-02-11 12:49:49 -07:00
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pci_pme_active(dev, false);
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2008-02-14 15:56:56 -07:00
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if (dev->is_added) {
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2005-04-28 01:25:49 -06:00
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pci_proc_detach_device(dev);
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pci_remove_sysfs_dev_files(dev);
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PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev()
After commit bcdde7e221a8 (sysfs: make __sysfs_remove_dir() recursive)
I'm seeing traces analogous to the one below in Thunderbolt testing:
WARNING: CPU: 3 PID: 76 at /scratch/rafael/work/linux-pm/fs/sysfs/group.c:214 sysfs_remove_group+0x59/0xe0()
sysfs group ffffffff81c6c500 not found for kobject '0000:08'
Modules linked in: ...
CPU: 3 PID: 76 Comm: kworker/u16:7 Not tainted 3.13.0-rc1+ #76
Hardware name: Acer Aspire S5-391/Venus , BIOS V1.02 05/29/2012
Workqueue: kacpi_hotplug acpi_hotplug_work_fn
0000000000000009 ffff8801644b9ac8 ffffffff816b23bf 0000000000000007
ffff8801644b9b18 ffff8801644b9b08 ffffffff81046607 ffff88016925b800
0000000000000000 ffffffff81c6c500 ffff88016924f928 ffff88016924f800
Call Trace:
[<ffffffff816b23bf>] dump_stack+0x4e/0x71
[<ffffffff81046607>] warn_slowpath_common+0x87/0xb0
[<ffffffff810466d1>] warn_slowpath_fmt+0x41/0x50
[<ffffffff811e42ef>] ? sysfs_get_dirent_ns+0x6f/0x80
[<ffffffff811e5389>] sysfs_remove_group+0x59/0xe0
[<ffffffff8149f00b>] dpm_sysfs_remove+0x3b/0x50
[<ffffffff81495818>] device_del+0x58/0x1c0
[<ffffffff814959c8>] device_unregister+0x48/0x60
[<ffffffff813254fe>] pci_remove_bus+0x6e/0x80
[<ffffffff81325548>] pci_remove_bus_device+0x38/0x110
[<ffffffff8132555d>] pci_remove_bus_device+0x4d/0x110
[<ffffffff81325639>] pci_stop_and_remove_bus_device+0x19/0x20
[<ffffffff813418d0>] disable_slot+0x20/0xe0
[<ffffffff81341a38>] acpiphp_check_bridge+0xa8/0xd0
[<ffffffff813427ad>] hotplug_event+0x17d/0x220
[<ffffffff81342880>] hotplug_event_work+0x30/0x70
[<ffffffff8136d665>] acpi_hotplug_work_fn+0x18/0x24
[<ffffffff81061331>] process_one_work+0x261/0x450
[<ffffffff81061a7e>] worker_thread+0x21e/0x370
[<ffffffff81061860>] ? rescuer_thread+0x300/0x300
[<ffffffff81068342>] kthread+0xd2/0xe0
[<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70
[<ffffffff816c19bc>] ret_from_fork+0x7c/0xb0
[<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70
(Mika Westerberg sees them too in his tests).
Some investigation documented in kernel bug #65281 led me to the
conclusion that the source of the problem is the device_del() in
pci_stop_dev() as it now causes the sysfs directory of the device to be
removed recursively along with all of its subdirectories. That includes
the sysfs directory of the device's subordinate bus (dev->subordinate) and
its "power" group.
Consequently, when pci_remove_bus() is called for dev->subordinate in
pci_remove_bus_device(), it calls device_unregister(&bus->dev), but at this
point the sysfs directory of bus->dev doesn't exist any more and its
"power" group doesn't exist either. Thus, when dpm_sysfs_remove() called
from device_del() tries to remove that group, it triggers the above
warning.
That indicates a logical mistake in the design of
pci_stop_and_remove_bus_device(), which causes bus device objects to be
left behind their parents (bridge device objects) and can be fixed by
moving the device_del() from pci_stop_dev() into pci_destroy_dev(), so
pci_remove_bus() can be called for the device's subordinate bus before the
device itself is unregistered from the hierarchy. Still, the driver, if
any, should be detached from the device in pci_stop_dev(), so use
device_release_driver() directly from there.
References: https://bugzilla.kernel.org/show_bug.cgi?id=65281#c6
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-12-18 13:53:32 -07:00
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device_release_driver(&dev->dev);
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2008-02-14 15:56:56 -07:00
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dev->is_added = 0;
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2005-04-28 01:25:49 -06:00
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}
|
PCI: add PCI Express ASPM support
PCI Express ASPM defines a protocol for PCI Express components in the D0
state to reduce Link power by placing their Links into a low power state
and instructing the other end of the Link to do likewise. This
capability allows hardware-autonomous, dynamic Link power reduction
beyond what is achievable by software-only controlled power management.
However, The device should be configured by software appropriately.
Enabling ASPM will save power, but will introduce device latency.
This patch adds ASPM support in Linux. It introduces a global policy for
ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control
it. The interface can be used as a boot option too. Currently we have
below setting:
-default, BIOS default setting
-powersave, highest power saving mode, enable all available ASPM
state and clock power management
-performance, highest performance, disable ASPM and clock power
management
By default, the 'default' policy is used currently.
In my test, power difference between powersave mode and performance mode
is about 1.3w in a system with 3 PCIE links.
Note: some devices might not work well with aspm, either because chipset
issue or device issue. The patch provide API (pci_disable_link_state),
driver can disable ASPM for specific device.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-24 18:46:41 -07:00
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if (dev->bus->self)
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pcie_aspm_exit_link_state(dev);
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2006-09-12 11:16:36 -06:00
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}
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static void pci_destroy_dev(struct pci_dev *dev)
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{
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2014-01-14 12:04:51 -07:00
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if (!dev->dev.kobj.parent)
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return;
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PCI: Move device_del() from pci_stop_dev() to pci_destroy_dev()
After commit bcdde7e221a8 (sysfs: make __sysfs_remove_dir() recursive)
I'm seeing traces analogous to the one below in Thunderbolt testing:
WARNING: CPU: 3 PID: 76 at /scratch/rafael/work/linux-pm/fs/sysfs/group.c:214 sysfs_remove_group+0x59/0xe0()
sysfs group ffffffff81c6c500 not found for kobject '0000:08'
Modules linked in: ...
CPU: 3 PID: 76 Comm: kworker/u16:7 Not tainted 3.13.0-rc1+ #76
Hardware name: Acer Aspire S5-391/Venus , BIOS V1.02 05/29/2012
Workqueue: kacpi_hotplug acpi_hotplug_work_fn
0000000000000009 ffff8801644b9ac8 ffffffff816b23bf 0000000000000007
ffff8801644b9b18 ffff8801644b9b08 ffffffff81046607 ffff88016925b800
0000000000000000 ffffffff81c6c500 ffff88016924f928 ffff88016924f800
Call Trace:
[<ffffffff816b23bf>] dump_stack+0x4e/0x71
[<ffffffff81046607>] warn_slowpath_common+0x87/0xb0
[<ffffffff810466d1>] warn_slowpath_fmt+0x41/0x50
[<ffffffff811e42ef>] ? sysfs_get_dirent_ns+0x6f/0x80
[<ffffffff811e5389>] sysfs_remove_group+0x59/0xe0
[<ffffffff8149f00b>] dpm_sysfs_remove+0x3b/0x50
[<ffffffff81495818>] device_del+0x58/0x1c0
[<ffffffff814959c8>] device_unregister+0x48/0x60
[<ffffffff813254fe>] pci_remove_bus+0x6e/0x80
[<ffffffff81325548>] pci_remove_bus_device+0x38/0x110
[<ffffffff8132555d>] pci_remove_bus_device+0x4d/0x110
[<ffffffff81325639>] pci_stop_and_remove_bus_device+0x19/0x20
[<ffffffff813418d0>] disable_slot+0x20/0xe0
[<ffffffff81341a38>] acpiphp_check_bridge+0xa8/0xd0
[<ffffffff813427ad>] hotplug_event+0x17d/0x220
[<ffffffff81342880>] hotplug_event_work+0x30/0x70
[<ffffffff8136d665>] acpi_hotplug_work_fn+0x18/0x24
[<ffffffff81061331>] process_one_work+0x261/0x450
[<ffffffff81061a7e>] worker_thread+0x21e/0x370
[<ffffffff81061860>] ? rescuer_thread+0x300/0x300
[<ffffffff81068342>] kthread+0xd2/0xe0
[<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70
[<ffffffff816c19bc>] ret_from_fork+0x7c/0xb0
[<ffffffff81068270>] ? flush_kthread_worker+0x70/0x70
(Mika Westerberg sees them too in his tests).
Some investigation documented in kernel bug #65281 led me to the
conclusion that the source of the problem is the device_del() in
pci_stop_dev() as it now causes the sysfs directory of the device to be
removed recursively along with all of its subdirectories. That includes
the sysfs directory of the device's subordinate bus (dev->subordinate) and
its "power" group.
Consequently, when pci_remove_bus() is called for dev->subordinate in
pci_remove_bus_device(), it calls device_unregister(&bus->dev), but at this
point the sysfs directory of bus->dev doesn't exist any more and its
"power" group doesn't exist either. Thus, when dpm_sysfs_remove() called
from device_del() tries to remove that group, it triggers the above
warning.
That indicates a logical mistake in the design of
pci_stop_and_remove_bus_device(), which causes bus device objects to be
left behind their parents (bridge device objects) and can be fixed by
moving the device_del() from pci_stop_dev() into pci_destroy_dev(), so
pci_remove_bus() can be called for the device's subordinate bus before the
device itself is unregistered from the hierarchy. Still, the driver, if
any, should be detached from the device in pci_stop_dev(), so use
device_release_driver() directly from there.
References: https://bugzilla.kernel.org/show_bug.cgi?id=65281#c6
Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2013-12-18 13:53:32 -07:00
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device_del(&dev->dev);
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2014-02-01 07:38:29 -07:00
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down_write(&pci_bus_sem);
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list_del(&dev->bus_list);
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up_write(&pci_bus_sem);
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pci_free_resources(dev);
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2013-01-21 14:20:46 -07:00
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put_device(&dev->dev);
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2005-04-16 16:20:36 -06:00
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}
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2012-08-16 20:43:11 -06:00
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void pci_remove_bus(struct pci_bus *bus)
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2005-04-16 16:20:36 -06:00
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{
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2012-08-16 20:43:11 -06:00
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pci_proc_detach_bus(bus);
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2005-04-16 16:20:36 -06:00
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2006-06-01 22:35:43 -06:00
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down_write(&pci_bus_sem);
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2012-08-16 20:43:11 -06:00
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list_del(&bus->node);
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pci_bus_release_busn_res(bus);
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2006-06-01 22:35:43 -06:00
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up_write(&pci_bus_sem);
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2012-08-16 20:43:11 -06:00
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pci_remove_legacy_files(bus);
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2013-04-11 23:44:20 -06:00
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pcibios_remove_bus(bus);
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2012-08-16 20:43:11 -06:00
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device_unregister(&bus->dev);
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2005-04-16 16:20:36 -06:00
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}
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EXPORT_SYMBOL(pci_remove_bus);
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2012-09-19 12:54:20 -06:00
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static void pci_stop_bus_device(struct pci_dev *dev)
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2006-09-12 11:16:36 -06:00
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{
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2012-08-17 11:25:01 -06:00
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struct pci_bus *bus = dev->subordinate;
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struct pci_dev *child, *tmp;
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/*
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2012-09-19 12:54:20 -06:00
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* Stopping an SR-IOV PF device removes all the associated VFs,
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2012-08-17 11:25:01 -06:00
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* which will update the bus->devices list and confuse the
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* iterator. Therefore, iterate in reverse so we remove the VFs
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* first, then the PF.
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*/
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2012-08-17 11:57:48 -06:00
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if (bus) {
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2012-08-17 11:25:01 -06:00
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list_for_each_entry_safe_reverse(child, tmp,
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&bus->devices, bus_list)
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2012-09-19 12:54:20 -06:00
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pci_stop_bus_device(child);
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}
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pci_stop_dev(dev);
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}
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static void pci_remove_bus_device(struct pci_dev *dev)
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{
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struct pci_bus *bus = dev->subordinate;
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struct pci_dev *child, *tmp;
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if (bus) {
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list_for_each_entry_safe(child, tmp,
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&bus->devices, bus_list)
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pci_remove_bus_device(child);
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2012-08-17 11:57:48 -06:00
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pci_remove_bus(bus);
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dev->subordinate = NULL;
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}
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2006-09-12 11:16:36 -06:00
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2012-08-17 11:57:48 -06:00
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pci_destroy_dev(dev);
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2006-09-12 11:16:36 -06:00
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}
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2012-09-19 12:54:20 -06:00
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/**
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* pci_stop_and_remove_bus_device - remove a PCI device and any children
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* @dev: the device to remove
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*
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* Remove a PCI device from the device lists, informing the drivers
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* that the device has been removed. We also remove any subordinate
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* buses and children in a depth-first manner.
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*
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* For each device we remove, delete the device structure from the
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* device lists, remove the /proc entry, and notify userspace
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* (/sbin/hotplug).
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*/
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void pci_stop_and_remove_bus_device(struct pci_dev *dev)
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{
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pci_stop_bus_device(dev);
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pci_remove_bus_device(dev);
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}
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2012-02-25 14:54:20 -07:00
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EXPORT_SYMBOL(pci_stop_and_remove_bus_device);
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2012-10-30 14:31:38 -06:00
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2014-01-10 07:22:18 -07:00
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void pci_stop_and_remove_bus_device_locked(struct pci_dev *dev)
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{
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pci_lock_rescan_remove();
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pci_stop_and_remove_bus_device(dev);
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pci_unlock_rescan_remove();
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}
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EXPORT_SYMBOL_GPL(pci_stop_and_remove_bus_device_locked);
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2012-10-30 14:31:38 -06:00
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void pci_stop_root_bus(struct pci_bus *bus)
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{
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struct pci_dev *child, *tmp;
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struct pci_host_bridge *host_bridge;
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if (!pci_is_root_bus(bus))
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return;
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host_bridge = to_pci_host_bridge(bus->bridge);
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list_for_each_entry_safe_reverse(child, tmp,
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&bus->devices, bus_list)
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pci_stop_bus_device(child);
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/* stop the host bridge */
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2013-11-30 15:40:27 -07:00
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device_release_driver(&host_bridge->dev);
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2012-10-30 14:31:38 -06:00
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}
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2015-04-08 12:21:33 -06:00
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EXPORT_SYMBOL_GPL(pci_stop_root_bus);
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2012-10-30 14:31:38 -06:00
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void pci_remove_root_bus(struct pci_bus *bus)
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{
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struct pci_dev *child, *tmp;
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struct pci_host_bridge *host_bridge;
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if (!pci_is_root_bus(bus))
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return;
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host_bridge = to_pci_host_bridge(bus->bridge);
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list_for_each_entry_safe(child, tmp,
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&bus->devices, bus_list)
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pci_remove_bus_device(child);
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pci_remove_bus(bus);
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host_bridge->bus = NULL;
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/* remove the host bridge */
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2013-11-30 15:40:27 -07:00
|
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device_unregister(&host_bridge->dev);
|
2012-10-30 14:31:38 -06:00
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}
|
2015-04-08 12:21:33 -06:00
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|
EXPORT_SYMBOL_GPL(pci_remove_root_bus);
|