PCI: Fix kerneldoc for pci_disable_link_state()

Fix kerneldoc for pci_disable_link_state().

[bhelgaas: expand comment, fix typos]
Signed-off-by: Yijing Wang <wangyijing@huawei.c

PCI: Fix kerneldoc for pci_disable_link_state()

Fix kerneldoc for pci_disable_link_state().

[bhelgaas: expand comment, fix typos]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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PCI/ASPM: Warn when driver asks to disable ASPM, but we can't do it

Some devices have hardware problems related to using ASPM. Drivers for
these devices use pci_disable_link_state() to

PCI/ASPM: Warn when driver asks to disable ASPM, but we can't do it

Some devices have hardware problems related to using ASPM. Drivers for
these devices use pci_disable_link_state() to prevent their device from
entering L0s or L1. But on platforms where the OS doesn't have permission
to manage ASPM, pci_disable_link_state() doesn't actually disable ASPM.

Windows has a similar mechanism ("PciASPMOptOut"), and when the OS doesn't
have control of ASPM, it doesn't actually disable ASPM either.

This patch just adds a warning in dmesg about the fact that
pci_disable_link_state() is doing nothing.

Reported-by: Emmanuel Grumbach <egrumbach@gmail.com>
Reference: https://lkml.kernel.org/r/CANUX_P3F5YhbZX3WGU-j1AGpbXb_T9Bis2ErhvKkFMtDvzatVQ@mail.gmail.com
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=57331
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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Merge tag 'pci-v3.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI changes from Bjorn Helgaas:
"Host bridge hotplug
- Major overhaul of ACPI host

Merge tag 'pci-v3.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI changes from Bjorn Helgaas:
"Host bridge hotplug
- Major overhaul of ACPI host bridge add/start (Rafael Wysocki, Yinghai Lu)
- Major overhaul of PCI/ACPI binding (Rafael Wysocki, Yinghai Lu)
- Split out ACPI host bridge and ACPI PCI device hotplug (Yinghai Lu)
- Stop caching _PRT and make independent of bus numbers (Yinghai Lu)

PCI device hotplug
- Clean up cpqphp dead code (Sasha Levin)
- Disable ARI unless device and upstream bridge support it (Yijing Wang)
- Initialize all hot-added devices (not functions 0-7) (Yijing Wang)

Power management
- Don't touch ASPM if disabled (Joe Lawrence)
- Fix ASPM link state management (Myron Stowe)

Miscellaneous
- Fix PCI_EXP_FLAGS accessor (Alex Williamson)
- Disable Bus Master in pci_device_shutdown (Konstantin Khlebnikov)
- Document hotplug resource and MPS parameters (Yijing Wang)
- Add accessor for PCIe capabilities (Myron Stowe)
- Drop pciehp suspend/resume messages (Paul Bolle)
- Make pci_slot built-in only (not a module) (Jiang Liu)
- Remove unused PCI/ACPI bind ops (Jiang Liu)
- Removed used pci_root_bus (Bjorn Helgaas)"

* tag 'pci-v3.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (51 commits)
PCI/ACPI: Don't cache _PRT, and don't associate them with bus numbers
PCI: Fix PCI Express Capability accessors for PCI_EXP_FLAGS
ACPI / PCI: Make pci_slot built-in only, not a module
PCI/PM: Clear state_saved during suspend
PCI: Use atomic_inc_return() rather than atomic_add_return()
PCI: Catch attempts to disable already-disabled devices
PCI: Disable Bus Master unconditionally in pci_device_shutdown()
PCI: acpiphp: Remove dead code for PCI host bridge hotplug
PCI: acpiphp: Create companion ACPI devices before creating PCI devices
PCI: Remove unused "rc" in virtfn_add_bus()
PCI: pciehp: Drop suspend/resume ENTRY messages
PCI/ASPM: Don't touch ASPM if forcibly disabled
PCI/ASPM: Deallocate upstream link state even if device is not PCIe
PCI: Document MPS parameters pci=pcie_bus_safe, pci=pcie_bus_perf, etc
PCI: Document hpiosize= and hpmemsize= resource reservation parameters
PCI: Use PCI Express Capability accessor
PCI: Introduce accessor to retrieve PCIe Capabilities Register
PCI: Put pci_dev in device tree as early as possible
PCI: Skip attaching driver in device_add()
PCI: acpiphp: Keep driver loaded even if no slots found
...

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PCI/ASPM: Don't touch ASPM if forcibly disabled

Don't allocate and track PCIe ASPM state when "pcie_aspm=off" is specified
on the kernel command line.

Based-on-patch-from: Matth

PCI/ASPM: Don't touch ASPM if forcibly disabled

Don't allocate and track PCIe ASPM state when "pcie_aspm=off" is specified
on the kernel command line.

Based-on-patch-from: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: David Bulkow <david.bulkow@stratus.com>
Acked-by: Myron Stowe <myron.stowe@redhat.com>

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PCI/ASPM: Deallocate upstream link state even if device is not PCIe

On PCI bus hotplug removal, pcie_aspm_exit_link_state() can potentially
skip parent devices that have link_state alloc

PCI/ASPM: Deallocate upstream link state even if device is not PCIe

On PCI bus hotplug removal, pcie_aspm_exit_link_state() can potentially
skip parent devices that have link_state allocated. Instead of exiting
early if a given device is not PCIe, check whether or not the device's
parent has link_state allocated. This enables pcie_aspm_exit_link_state()
to properly clean up parent link_state when the last function in a slot
might not be PCIe.

Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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PCI: Allow pcie_aspm=force even when FADT indicates it is unsupported

Right now using pcie_aspm=force will not enable ASPM if the FADT indicates
ASPM is unsupported. However, the semant

PCI: Allow pcie_aspm=force even when FADT indicates it is unsupported

Right now using pcie_aspm=force will not enable ASPM if the FADT indicates
ASPM is unsupported. However, the semantics of force should probably allow
for this, especially as they did before 3c076351c4 ("PCI: Rework ASPM
disable code")

This patch just skips the clearing of any ASPM setup that the firmware has
carried out on this bus if pcie_aspm=force is being used.

Reference: http://bugs.launchpad.net/bugs/962038
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org

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Merge branch 'pci/bjorn-pcie-cap' into next

* pci/bjorn-pcie-cap:
ath9k: Use standard #defines for PCIe Capability ASPM fields
iwlwifi: Use standard #defines for PCIe Capability

Merge branch 'pci/bjorn-pcie-cap' into next

* pci/bjorn-pcie-cap:
ath9k: Use standard #defines for PCIe Capability ASPM fields
iwlwifi: Use standard #defines for PCIe Capability ASPM fields
iwlwifi: collapse wrapper for pcie_capability_read_word()
iwlegacy: Use standard #defines for PCIe Capability ASPM fields
iwlegacy: collapse wrapper for pcie_capability_read_word()
cxgb3: Use standard #defines for PCIe Capability ASPM fields
PCI: Add standard PCIe Capability Link ASPM field names
PCI/portdrv: Use PCI Express Capability accessors
PCI: Use standard PCIe Capability Link register field names
PCI: Add and use standard PCI-X Capability register names

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PCI: Add standard PCIe Capability Link ASPM field names

Add standard #defines for ASPM fields in PCI Express Link Capability and
Link Control registers.

Previously we used PCIE_

PCI: Add standard PCIe Capability Link ASPM field names

Add standard #defines for ASPM fields in PCI Express Link Capability and
Link Control registers.

Previously we used PCIE_LINK_STATE_L0S and PCIE_LINK_STATE_L1 directly, but
these are defined for the Linux ASPM interfaces, e.g.,
pci_disable_link_state(), and only coincidentally match the actual register
bits. PCIE_LINK_STATE_CLKPM, also part of that interface, does not match
the register bit.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

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PCI: Convert dev_printk(KERN_<LEVEL> to dev_<level>(

dev_<level> calls take less code than dev_printk(KERN_<LEVEL>
and reducing object size is good.
Coalesce formats for easier grep.

PCI: Convert dev_printk(KERN_<LEVEL> to dev_<level>(

dev_<level> calls take less code than dev_printk(KERN_<LEVEL>
and reducing object size is good.
Coalesce formats for easier grep.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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PCI/ASPM: Use PCI Express Capability accessors

Use PCI Express Capability access functions to simplify PCIe ASPM.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by:

PCI/ASPM: Use PCI Express Capability accessors

Use PCI Express Capability access functions to simplify PCIe ASPM.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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PCI: Introduce pci_pcie_type(dev) to replace pci_dev->pcie_type

Introduce an inline function pci_pcie_type(dev) to extract PCIe
device type from pci_dev->pcie_flags_reg field, and prepar

PCI: Introduce pci_pcie_type(dev) to replace pci_dev->pcie_type

Introduce an inline function pci_pcie_type(dev) to extract PCIe
device type from pci_dev->pcie_flags_reg field, and prepare for
removing pci_dev->pcie_type.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

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ASPM: Fix pcie devices with non-pcie children

Since 3.2.12 and 3.3, some systems are failing to boot with a BUG_ON.
Some other systems using the pata_jmicron driver fail to boot because

ASPM: Fix pcie devices with non-pcie children

Since 3.2.12 and 3.3, some systems are failing to boot with a BUG_ON.
Some other systems using the pata_jmicron driver fail to boot because no
disks are detected. Passing pcie_aspm=force on the kernel command line
works around it.

The cause: commit 4949be16822e ("PCI: ignore pre-1.1 ASPM quirking when
ASPM is disabled") changed the behaviour of pcie_aspm_sanity_check() to
always return 0 if aspm is disabled, in order to avoid cases where we
changed ASPM state on pre-PCIe 1.1 devices.

This skipped the secondary function of pcie_aspm_sanity_check which was
to avoid us enabling ASPM on devices that had non-PCIe children, causing
trouble later on. Move the aspm_disabled check so we continue to honour
that scenario.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=42979 and
http://bugs.debian.org/665420

Reported-by: Romain Francoise <romain@orebokech.com> # kernel panic
Reported-by: Chris Holland <bandidoirlandes@gmail.com> # disk detection trouble
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Tested-by: Hatem Masmoudi <hatem.masmoudi@gmail.com> # Dell Latitude E5520
Tested-by: janek <jan0x6c@gmail.com> # pata_jmicron with JMB362/JMB363
[jn: with more symptoms in log message]
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci

Pull PCI changes (including maintainer change) from Jesse Barnes:
"This pull has some good cleanup

Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci

Pull PCI changes (including maintainer change) from Jesse Barnes:
"This pull has some good cleanups from Bjorn and Yinghai, as well as
some more code from Yinghai to better handle resource re-allocation
when enabled.

There's also a new initcall_debug feature from Arjan which will print
out quirk timing information to help identify slow quirks for fixing
or refinement (Yinghai sent in a few patches to do just that once the
new debug code landed).

Beyond that, I'm handing off PCI maintainership to Bjorn Helgaas.
He's been a core PCI and Linux contributor for some time now, and has
kindly volunteered to take over. I just don't feel I have the time
for PCI review and work that it deserves lately (I've taken on some
other projects), and haven't been as responsive lately as I'd like, so
I approached Bjorn asking if he'd like to manage things. He's going
to give it a try, and I'm confident he'll do at least as well as I
have in keeping the tree managed, patches flowing, and keeping things
stable."

Fix up some fairly trivial conflicts due to other cleanups (mips device
resource fixup cleanups clashing with list handling cleanup, ppc iseries
removal clashing with pci_probe_only cleanup etc)

* 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci: (112 commits)
PCI: Bjorn gets PCI hotplug too
PCI: hand PCI maintenance over to Bjorn Helgaas
unicore32/PCI: move <asm-generic/pci-bridge.h> include to asm/pci.h
sparc/PCI: convert devtree and arch-probed bus addresses to resource
powerpc/PCI: allow reallocation on PA Semi
powerpc/PCI: convert devtree bus addresses to resource
powerpc/PCI: compute I/O space bus-to-resource offset consistently
arm/PCI: don't export pci_flags
PCI: fix bridge I/O window bus-to-resource conversion
x86/PCI: add spinlock held check to 'pcibios_fwaddrmap_lookup()'
PCI / PCIe: Introduce command line option to disable ARI
PCI: make acpihp use __pci_remove_bus_device instead
PCI: export __pci_remove_bus_device
PCI: Rename pci_remove_behind_bridge to pci_stop_and_remove_behind_bridge
PCI: Rename pci_remove_bus_device to pci_stop_and_remove_bus_device
PCI: print out PCI device info along with duration
PCI: Move "pci reassigndev resource alignment" out of quirks.c
PCI: Use class for quirk for usb host controller fixup
PCI: Use class for quirk for ti816x class fixup
PCI: Use class for quirk for intel e100 interrupt fixup
...

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PCI: ignore pre-1.1 ASPM quirking when ASPM is disabled

Right now we won't touch ASPM state if ASPM is disabled, except in the case
where we find a device that appears to be too old to r

PCI: ignore pre-1.1 ASPM quirking when ASPM is disabled

Right now we won't touch ASPM state if ASPM is disabled, except in the case
where we find a device that appears to be too old to reliably support ASPM.
Right now we'll clear it in that case, which is almost certainly the wrong
thing to do. The easiest way around this is just to disable the blacklisting
when ASPM is disabled.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCI: pcie: Add support for setting default ASPM policy

Distributions may wish to provide different defaults for PCIE ASPM
depending on their target audience. Provide a configuration opti

PCI: pcie: Add support for setting default ASPM policy

Distributions may wish to provide different defaults for PCIE ASPM
depending on their target audience. Provide a configuration option for
choosing the default policy.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCI: Rework ASPM disable code

Right now we forcibly clear ASPM state on all devices if the BIOS indicates
that the feature isn't supported. Based on the Microsoft presentation
"PCI E

PCI: Rework ASPM disable code

Right now we forcibly clear ASPM state on all devices if the BIOS indicates
that the feature isn't supported. Based on the Microsoft presentation
"PCI Express In Depth for Windows Vista and Beyond", I'm starting to think
that this may be an error. The implication is that unless the platform
grants full control via _OSC, Windows will not touch any PCIe features -
including ASPM. In that case clearing ASPM state would be an error unless
the platform has granted us that control.

This patch reworks the ASPM disabling code such that the actual clearing
of state is triggered by a successful handoff of PCIe control to the OS.
The general ASPM code undergoes some changes in order to ensure that the
ability to clear the bits isn't overridden by ASPM having already been
disabled. Further, this theoretically now allows for situations where
only a subset of PCIe roots hand over control, leaving the others in the
BIOS state.

It's difficult to know for sure that this is the right thing to do -
there's zero public documentation on the interaction between all of these
components. But enough vendors enable ASPM on platforms and then set this
bit that it seems likely that they're expecting the OS to leave them alone.

Measured to save around 5W on an idle Thinkpad X220.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCIe ASPM: forcedly -> forcibly

Merriam-Webster tells us that the word exists. However ...

* Google suggests `forcibly' because it doesn't recognize `forcedly'.
* Google lis

PCIe ASPM: forcedly -> forcibly

Merriam-Webster tells us that the word exists. However ...

* Google suggests `forcibly' because it doesn't recognize `forcedly'.
* Google lists 494 thousand results for `forcedly'.
* Google lists 13.7 million results for `forcibly'.
* Linus's repo contains 1 occurrence of `forcedly' ( 0 after my change).
* Linus's repo contains 60 occurrences of `forcibly' (61 after my change).

Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

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PCI/e1000e: Add and use pci_disable_link_state_locked()

Need to use it in _e1000e_disable_aspm. This routine is used for error
recovery, where the pci_bus_sem is already held, and we do

PCI/e1000e: Add and use pci_disable_link_state_locked()

Need to use it in _e1000e_disable_aspm. This routine is used for error
recovery, where the pci_bus_sem is already held, and we don't want
pci_disable_link_state to try to take it again. So add a locked variant
for use in cases like this.

Found lock up:

[ 2374.654557] kworker/32:1 D ffff881027f6b0f0 0 6075 2 0x00000000
[ 2374.654816] ffff88503f099a68 0000000000000046 ffff88503f098000 0000000000004000
[ 2374.654837] 00000000001d1ec0 ffff88503f099fd8 00000000001d1ec0 ffff88503f099fd8
[ 2374.654860] 0000000000004000 00000000001d1ec0 ffff88503dcc8000 ffff88503f090000
[ 2374.654880] Call Trace:
[ 2374.654898] [<ffffffff810b1302>] ? __lock_acquired+0x3a/0x224
[ 2374.654914] [<ffffffff81c2b59c>] ? _raw_spin_unlock_irq+0x30/0x36
[ 2374.654925] [<ffffffff810b069d>] ? trace_hardirqs_on_caller+0x1f/0x178
[ 2374.654936] [<ffffffff81c2ab24>] rwsem_down_failed_common+0xd3/0x103
[ 2374.654945] [<ffffffff810b158f>] ? __lock_contended+0x3a/0x2a2
[ 2374.654955] [<ffffffff81c2ab7b>] rwsem_down_read_failed+0x12/0x14
[ 2374.654967] [<ffffffff813371e4>] call_rwsem_down_read_failed+0x14/0x30
[ 2374.654981] [<ffffffff8135df20>] ? pci_disable_link_state+0x5f/0xf5
[ 2374.654990] [<ffffffff81c2a0e6>] ? down_read+0x7e/0x91
[ 2374.654999] [<ffffffff8135df20>] ? pci_disable_link_state+0x5f/0xf5
[ 2374.655008] [<ffffffff8135df20>] pci_disable_link_state+0x5f/0xf5
[ 2374.655024] [<ffffffff81661796>] e1000e_disable_aspm+0x55/0x5a
[ 2374.655037] [<ffffffff816677eb>] e1000_io_slot_reset+0x59/0xea
[ 2374.655048] [<ffffffff8135fe0d>] ? report_mmio_enabled+0x5d/0x5d
[ 2374.655057] [<ffffffff8135fe3b>] report_slot_reset+0x2e/0x5d
[ 2374.655072] [<ffffffff8135369e>] pci_walk_bus+0x8a/0xb7
[ 2374.655081] [<ffffffff8135fe0d>] ? report_mmio_enabled+0x5d/0x5d
[ 2374.655091] [<ffffffff813603be>] broadcast_error_message+0xa4/0xb2
[ 2374.655101] [<ffffffff81352c71>] ? pci_bus_read_config_dword+0x72/0x80
[ 2374.655110] [<ffffffff813606df>] do_recovery+0x9e/0xf9
[ 2374.655120] [<ffffffff81360786>] handle_error_source+0x4c/0x51
[ 2374.655129] [<ffffffff81360974>] aer_isr_one_error+0x1e9/0x21a
[ 2374.655138] [<ffffffff81360a6c>] aer_isr+0xc7/0xcc
[ 2374.655147] [<ffffffff813609a5>] ? aer_isr_one_error+0x21a/0x21a
[ 2374.655159] [<ffffffff81096d9f>] process_one_work+0x237/0x3ec
[ 2374.655168] [<ffffffff81096d10>] ? process_one_work+0x1a8/0x3ec
[ 2374.655178] [<ffffffff8109728d>] worker_thread+0x17c/0x240
[ 2374.655186] [<ffffffff810b0803>] ? trace_hardirqs_on+0xd/0xf
[ 2374.655196] [<ffffffff81097111>] ? manage_workers+0xab/0xab
[ 2374.655209] [<ffffffff8109c8ed>] kthread+0xa0/0xa8
[ 2374.655223] [<ffffffff81c332d4>] kernel_thread_helper+0x4/0x10
[ 2374.655232] [<ffffffff81c2b880>] ? retint_restore_args+0xe/0xe
[ 2374.655243] [<ffffffff8109c84d>] ? __init_kthread_worker+0x5b/0x5b
[ 2374.655252] [<ffffffff81c332d0>] ? gs_change+0xb/0xb

when aer happens,
pci_walk_bus already have down_read(&pci_bus_sem)...
then report_slot_reset
==> e1000_io_slot_reset
==> e1000e_disable_aspm
==> pci_disable_link_state...

We can not use pci_disable_link_state, and it will try to hold pci_bus_sem again.

Try to have __pci_disable_link_state that will not need to hold pci_bus_sem.

-v2: change name to pci_disable_link_state_locked() according to Jesse.

[jbarnes: make sure new function is exported for modules]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCI: Enable ASPM state clearing regardless of policy

Commit 2f671e2d allowed us to clear ASPM state when the FADT
tells us it isn't supported, but we don't put this into effect
if th

PCI: Enable ASPM state clearing regardless of policy

Commit 2f671e2d allowed us to clear ASPM state when the FADT
tells us it isn't supported, but we don't put this into effect
if the aspm_policy is set to POLICY_POWERSAVE. Enable the
state to be cleared regardless of policy.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

show more ...

PCI: Changing ASPM policy, via /sys, to POWERSAVE could cause NMIs

v3 -> v2: Modified the text that describes the problem
v2 -> v1: Returned -EPERM
v1 : http://marc.info/?l=linu

PCI: Changing ASPM policy, via /sys, to POWERSAVE could cause NMIs

v3 -> v2: Modified the text that describes the problem
v2 -> v1: Returned -EPERM
v1 : http://marc.info/?l=linux-pci&m=130013194803727&w=2

For servers whose hardware cannot handle ASPM the BIOS ought to set the
FADT bit shown below:
In Sec 5.2.9.3 (IA-PC Boot Arch. Flags) of ACPI4.0a Specification, please
see Table 5-11:
PCIe ASPM Controls: If set, indicates to OSPM that it must not enable
OPSM ASPM control on this platform.

However there are shipping servers whose BIOS did not set this bit. (An
example is the HP ProLiant DL385 G6. A Maintenance BIOS will fix that).
For such servers even if a call is made via pci_no_aspm(), based on _OSC
support in the BIOS, it may be too late because the ASPM code may have
already allocated and filled its "link_list".

So if a user sets the ASPM "policy" to "powersave" via /sys then
pcie_aspm_set_policy() will run through the "link_list" and re-configure
ASPM policy on devices that advertise ASPM L0s/L1 capability:
# echo powersave > /sys/module/pcie_aspm/parameters/policy
# cat /sys/module/pcie_aspm/parameters/policy
default performance [powersave]

That can cause NMIs since the hardware doesn't play well with ASPM:
[ 1651.906015] NMI: PCI system error (SERR) for reason b1 on CPU 0.
[ 1651.906015] Dazed and confused, but trying to continue

Ideally, the BIOS should have set that FADT bit in the first place but we
could be more robust - especially given the fact that Windows doesn't
cause NMIs in the above scenario.

There should be a sanity check to not allow a user to modify ASPM policy
when aspm_disabled is set.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

show more ...

PCI: PCIe links may not get configured for ASPM under POWERSAVE mode

v3 -> v2: Moved ASPM enabling logic to pci_set_power_state()
v2 -> v1: Preserved the logic in pci_raw_set_power_state

PCI: PCIe links may not get configured for ASPM under POWERSAVE mode

v3 -> v2: Moved ASPM enabling logic to pci_set_power_state()
v2 -> v1: Preserved the logic in pci_raw_set_power_state()
: Added ASPM enabling logic after scanning Root Bridge
: http://marc.info/?l=linux-pci&m=130046996216391&w=2
v1 : http://marc.info/?l=linux-pci&m=130013164703283&w=2

The assumption made in commit 41cd766b065970ff6f6c89dd1cf55fa706c84a3d
(PCI: Don't enable aspm before drivers have had a chance to veto it) that
pci_enable_device() will result in re-configuring ASPM when aspm_policy is
POWERSAVE is no longer valid. This is due to commit
97c145f7c87453cec90e91238fba5fe2c1561b32 (PCI: read current power state
at enable time) which resets dev->current_state to D0. Due to this the
call to pcie_aspm_pm_state_change() is never made. Note the equality check
(below) that returns early:
./drivers/pci/pci.c: pci_raw_set_pci_power_state()
546 /* Check if we're already there */
547 if (dev->current_state == state)
548 return 0;

Therefore OSPM never configures the PCIe links for ASPM to turn them "on".

Fix it by configuring ASPM from the pci_enable_device() code path. This
also allows a driver such as the e1000e networking driver a chance to
disable ASPM (L0s, L1), if need be, prior to enabling the device. A
driver may perform this action if the device is known to mis-behave
wrt ASPM.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCI/ACPI: Report ASPM support to BIOS if not disabled from command line

We need to distinguish the situation in which ASPM support is
disabled from the command line or through .config fr

PCI/ACPI: Report ASPM support to BIOS if not disabled from command line

We need to distinguish the situation in which ASPM support is
disabled from the command line or through .config from the situation
in which it is disabled, because the hardware or BIOS can't handle
it. In the former case we should not report ASPM support to the BIOS
through ACPI _OSC, but in the latter case we should do that.

Introduce pcie_aspm_support_enabled() that can be used by
acpi_pci_root_add() to determine whether or not it should report ASPM
support to the BIOS through _OSC.

Cc: stable@kernel.org
References: https://bugzilla.kernel.org/show_bug.cgi?id=29722
References: https://bugzilla.kernel.org/show_bug.cgi?id=20232
Reported-and-tested-by: Ortwin Glück <odi@odi.ch>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCI: Disable ASPM if BIOS asks us to

We currently refuse to touch the ASPM registers if the BIOS tells us that
ASPM isn't supported. This can cause problems if the BIOS has (for any

PCI: Disable ASPM if BIOS asks us to

We currently refuse to touch the ASPM registers if the BIOS tells us that
ASPM isn't supported. This can cause problems if the BIOS has (for any
reason) enabled ASPM on some devices anyway. Change the code such that we
explicitly clear ASPM if the FADT indicates that ASPM isn't supported,
and make sure we tidy up appropriately on device removal in order to deal
with the hotplug case. If ASPM is disabled because the BIOS doesn't hand
over control then we won't touch the registers.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCI: Don't enable aspm before drivers have had a chance to veto it

The aspm code will currently set the configured aspm policy before drivers
have had an opportunity to indicate that the

PCI: Don't enable aspm before drivers have had a chance to veto it

The aspm code will currently set the configured aspm policy before drivers
have had an opportunity to indicate that their hardware doesn't support it.
Unfortunately, putting some hardware in L0 or L1 can result in the hardware
no longer responding to any requests, even after aspm is disabled. It makes
more sense to leave aspm policy at the BIOS defaults at initial setup time,
reconfiguring it after pci_enable_device() is called. This allows the
driver to blacklist individual devices beforehand.

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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PCI: change PCI nomenclature in drivers/pci/ (comment changes)

Changing occurrences of variants of PCI-X and PCIe to the PCI-SIG
terms listed in the "Trademark and Logo Usage Guidelines"

PCI: change PCI nomenclature in drivers/pci/ (comment changes)

Changing occurrences of variants of PCI-X and PCIe to the PCI-SIG
terms listed in the "Trademark and Logo Usage Guidelines".
http://www.pcisig.com/developers/procedures/logos/Trademark_and_Logo_Usage_Guidelines_updated_112206.pdf

Patch is limited to drivers/pci/ and changes concern comments only.

Signed-off-by: Stefan Assmann <sassmann@redhat.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

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