<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/pci/bus.c, branch v4.18-rc4</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>PCI: remove CONFIG_PCI_BUS_ADDR_T_64BIT</title>
<updated>2018-05-09T04:57:18+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2018-04-03T14:40:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=8e6390795eacf87f717bc755f352f0aa85da5700'/>
<id>8e6390795eacf87f717bc755f352f0aa85da5700</id>
<content type='text'>
This symbol is now always identical to CONFIG_ARCH_DMA_ADDR_T_64BIT, so
remove it.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Acked-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This symbol is now always identical to CONFIG_ARCH_DMA_ADDR_T_64BIT, so
remove it.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Acked-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Tidy comments</title>
<updated>2018-03-19T19:20:43+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2018-03-09T22:36:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=df62ab5e0f75608919df7442654b0fab78246b7b'/>
<id>df62ab5e0f75608919df7442654b0fab78246b7b</id>
<content type='text'>
Remove pointless comments that tell us the file name, remove blank line
comments, follow multi-line comment conventions.  No functional change
intended.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Remove pointless comments that tell us the file name, remove blank line
comments, follow multi-line comment conventions.  No functional change
intended.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'pci/spdx' into next</title>
<updated>2018-02-01T17:40:07+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2018-02-01T17:40:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ab8c609356fbe8dbcd44df11e884ce8cddf3739e'/>
<id>ab8c609356fbe8dbcd44df11e884ce8cddf3739e</id>
<content type='text'>
* pci/spdx:
  PCI: Add SPDX GPL-2.0+ to replace implicit GPL v2 or later statement
  PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate
  PCI: Add SPDX GPL-2.0 to replace COPYING boilerplate
  PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
  PCI: Add SPDX GPL-2.0 when no license was specified
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* pci/spdx:
  PCI: Add SPDX GPL-2.0+ to replace implicit GPL v2 or later statement
  PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate
  PCI: Add SPDX GPL-2.0 to replace COPYING boilerplate
  PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
  PCI: Add SPDX GPL-2.0 when no license was specified
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Add SPDX GPL-2.0 when no license was specified</title>
<updated>2018-01-26T17:45:16+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2018-01-26T17:45:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7328c8f48d1895b3fec98b0b319cfb856b4c4fa1'/>
<id>7328c8f48d1895b3fec98b0b319cfb856b4c4fa1</id>
<content type='text'>
b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") added SPDX GPL-2.0 to several PCI files that
previously contained no license information.

Add SPDX GPL-2.0 to all other PCI files that did not contain any license
information and hence were under the default GPL version 2 license of the
kernel.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
b24413180f56 ("License cleanup: add SPDX GPL-2.0 license identifier to
files with no license") added SPDX GPL-2.0 to several PCI files that
previously contained no license information.

Add SPDX GPL-2.0 to all other PCI files that did not contain any license
information and hence were under the default GPL version 2 license of the
kernel.

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Add wrappers for dev_printk()</title>
<updated>2018-01-18T18:55:24+00:00</updated>
<author>
<name>Frederick Lawler</name>
<email>fred@fredlawl.com</email>
</author>
<published>2018-01-18T18:55:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=7506dc7989933235e6fc23f3d0516bdbf0f7d1a8'/>
<id>7506dc7989933235e6fc23f3d0516bdbf0f7d1a8</id>
<content type='text'>
Add PCI-specific dev_printk() wrappers and use them to simplify the code
slightly.  No functional change intended.

Signed-off-by: Frederick Lawler &lt;fred@fredlawl.com&gt;
[bhelgaas: squash into one patch]
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add PCI-specific dev_printk() wrappers and use them to simplify the code
slightly.  No functional change intended.

Signed-off-by: Frederick Lawler &lt;fred@fredlawl.com&gt;
[bhelgaas: squash into one patch]
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Autosense device removal in pci_bridge_d3_update()</title>
<updated>2016-11-18T00:44:56+00:00</updated>
<author>
<name>Lukas Wunner</name>
<email>lukas@wunner.de</email>
</author>
<published>2016-10-28T08:52:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=1ed276a7b9d84626e5243fc54863440c74a4100a'/>
<id>1ed276a7b9d84626e5243fc54863440c74a4100a</id>
<content type='text'>
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-&gt;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 &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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-&gt;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 &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Reviewed-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branches 'pci/demodularize-hosts' and 'pci/host-request-windows' into next</title>
<updated>2016-08-01T17:23:57+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2016-08-01T17:23:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=79dd99346166bcbf3b082f6e234db788da1db3c9'/>
<id>79dd99346166bcbf3b082f6e234db788da1db3c9</id>
<content type='text'>
* pci/demodularize-hosts:
  PCI: xgene: Make explicitly non-modular
  PCI: thunder-pem: Make explicitly non-modular
  PCI: thunder-ecam: Make explicitly non-modular
  PCI: tegra: Make explicitly non-modular
  PCI: rcar-gen2: Make explicitly non-modular
  PCI: rcar: Make explicitly non-modular
  PCI: mvebu: Make explicitly non-modular
  PCI: layerscape: Make explicitly non-modular
  PCI: keystone: Make explicitly non-modular
  PCI: hisi: Make explicitly non-modular
  PCI: generic: Make explicitly non-modular
  PCI: designware-plat: Make it explicitly non-modular
  PCI: artpec6: Make explicitly non-modular
  PCI: armada8k: Make explicitly non-modular
  PCI: artpec: Add PCI_MSI_IRQ_DOMAIN dependency
  PCI: artpec: Add Axis ARTPEC-6 PCIe controller driver
  PCI: Add DT binding for Axis ARTPEC-6 PCIe controller
  PCI: generic: Select IRQ_DOMAIN

* pci/host-request-windows:
  PCI: versatile: Simplify host bridge window iteration
  PCI: versatile: Request host bridge window resources with core function
  PCI: tegra: Request host bridge window resources with core function
  PCI: tegra: Remove top-level resource from hierarchy
  PCI: rcar: Simplify host bridge window iteration
  PCI: rcar: Request host bridge window resources with core function
  PCI: rcar Gen2: Request host bridge window resources
  PCI: rcar: Drop gen2 dummy I/O port region
  ARM: Make PCI I/O space optional
  PCI: mvebu: Request host bridge window resources with core function
  PCI: generic: Simplify host bridge window iteration
  PCI: generic: Request host bridge window resources with core function
  PCI: altera: Simplify host bridge window iteration
  PCI: altera: Request host bridge window resources with core function
  PCI: xilinx-nwl: Use dev_printk() when possible
  PCI: xilinx-nwl: Request host bridge window resources
  PCI: xilinx-nwl: Free bridge resource list on failure
  PCI: xilinx: Request host bridge window resources
  PCI: xilinx: Free bridge resource list on failure
  PCI: xgene: Request host bridge window resources
  PCI: xgene: Free bridge resource list on failure
  PCI: iproc: Request host bridge window resources
  PCI: designware: Simplify host bridge window iteration
  PCI: designware: Request host bridge window resources
  PCI: designware: Free bridge resource list on failure
  PCI: Add devm_request_pci_bus_resources()
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
* pci/demodularize-hosts:
  PCI: xgene: Make explicitly non-modular
  PCI: thunder-pem: Make explicitly non-modular
  PCI: thunder-ecam: Make explicitly non-modular
  PCI: tegra: Make explicitly non-modular
  PCI: rcar-gen2: Make explicitly non-modular
  PCI: rcar: Make explicitly non-modular
  PCI: mvebu: Make explicitly non-modular
  PCI: layerscape: Make explicitly non-modular
  PCI: keystone: Make explicitly non-modular
  PCI: hisi: Make explicitly non-modular
  PCI: generic: Make explicitly non-modular
  PCI: designware-plat: Make it explicitly non-modular
  PCI: artpec6: Make explicitly non-modular
  PCI: armada8k: Make explicitly non-modular
  PCI: artpec: Add PCI_MSI_IRQ_DOMAIN dependency
  PCI: artpec: Add Axis ARTPEC-6 PCIe controller driver
  PCI: Add DT binding for Axis ARTPEC-6 PCIe controller
  PCI: generic: Select IRQ_DOMAIN

* pci/host-request-windows:
  PCI: versatile: Simplify host bridge window iteration
  PCI: versatile: Request host bridge window resources with core function
  PCI: tegra: Request host bridge window resources with core function
  PCI: tegra: Remove top-level resource from hierarchy
  PCI: rcar: Simplify host bridge window iteration
  PCI: rcar: Request host bridge window resources with core function
  PCI: rcar Gen2: Request host bridge window resources
  PCI: rcar: Drop gen2 dummy I/O port region
  ARM: Make PCI I/O space optional
  PCI: mvebu: Request host bridge window resources with core function
  PCI: generic: Simplify host bridge window iteration
  PCI: generic: Request host bridge window resources with core function
  PCI: altera: Simplify host bridge window iteration
  PCI: altera: Request host bridge window resources with core function
  PCI: xilinx-nwl: Use dev_printk() when possible
  PCI: xilinx-nwl: Request host bridge window resources
  PCI: xilinx-nwl: Free bridge resource list on failure
  PCI: xilinx: Request host bridge window resources
  PCI: xilinx: Free bridge resource list on failure
  PCI: xgene: Request host bridge window resources
  PCI: xgene: Free bridge resource list on failure
  PCI: iproc: Request host bridge window resources
  PCI: designware: Simplify host bridge window iteration
  PCI: designware: Request host bridge window resources
  PCI: designware: Free bridge resource list on failure
  PCI: Add devm_request_pci_bus_resources()
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Put PCIe ports into D3 during suspend</title>
<updated>2016-06-13T19:57:36+00:00</updated>
<author>
<name>Mika Westerberg</name>
<email>mika.westerberg@linux.intel.com</email>
</author>
<published>2016-06-02T08:17:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9d26d3a8f1b0c442339a235f9508bdad8af91043'/>
<id>9d26d3a8f1b0c442339a235f9508bdad8af91043</id>
<content type='text'>
Currently the Linux PCI core does not touch power state of PCI bridges and
PCIe ports when system suspend is entered.  Leaving them in D0 consumes
power unnecessarily and may prevent the CPU from entering deeper C-states.

With recent PCIe hardware we can power down the ports to save power given
that we take into account few restrictions:

  - The PCIe port hardware is recent enough, starting from 2015.

  - Devices connected to PCIe ports are effectively in D3cold once the port
    is transitioned to D3 (the config space is not accessible anymore and
    the link may be powered down).

  - Devices behind the PCIe port need to be allowed to transition to D3cold
    and back.  There is a way both drivers and userspace can forbid this.

  - If the device behind the PCIe port is capable of waking the system it
    needs to be able to do so from D3cold.

This patch adds a new flag to struct pci_device called 'bridge_d3'.  This
flag is set and cleared by the PCI core whenever there is a change in power
management state of any of the devices behind the PCIe port.  When system
later on is suspended we only need to check this flag and if it is true
transition the port to D3 otherwise we leave it in D0.

Also provide override mechanism via command line parameter
"pcie_port_pm=[off|force]" that can be used to disable or enable the
feature regardless of the BIOS manufacturing date.

Tested-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Signed-off-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently the Linux PCI core does not touch power state of PCI bridges and
PCIe ports when system suspend is entered.  Leaving them in D0 consumes
power unnecessarily and may prevent the CPU from entering deeper C-states.

With recent PCIe hardware we can power down the ports to save power given
that we take into account few restrictions:

  - The PCIe port hardware is recent enough, starting from 2015.

  - Devices connected to PCIe ports are effectively in D3cold once the port
    is transitioned to D3 (the config space is not accessible anymore and
    the link may be powered down).

  - Devices behind the PCIe port need to be allowed to transition to D3cold
    and back.  There is a way both drivers and userspace can forbid this.

  - If the device behind the PCIe port is capable of waking the system it
    needs to be able to do so from D3cold.

This patch adds a new flag to struct pci_device called 'bridge_d3'.  This
flag is set and cleared by the PCI core whenever there is a change in power
management state of any of the devices behind the PCIe port.  When system
later on is suspended we only need to check this flag and if it is true
transition the port to D3 otherwise we leave it in D0.

Also provide override mechanism via command line parameter
"pcie_port_pm=[off|force]" that can be used to disable or enable the
feature regardless of the BIOS manufacturing date.

Tested-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Signed-off-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Add devm_request_pci_bus_resources()</title>
<updated>2016-06-06T20:25:51+00:00</updated>
<author>
<name>Bjorn Helgaas</name>
<email>bhelgaas@google.com</email>
</author>
<published>2016-05-28T23:09:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=950334bcf17a6ab55ce13d3bdf050f7b429320d5'/>
<id>950334bcf17a6ab55ce13d3bdf050f7b429320d5</id>
<content type='text'>
Several host bridge drivers iterate through the list of bridge windows to
request resources.  Several others don't request the window resources at
all.

Add a devm_request_pci_bus_resources() interface to make it easier for
drivers to request all the window resources.  Export to GPL modules (from
Arnd Bergmann &lt;arnd@arndb.de&gt;).

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Several host bridge drivers iterate through the list of bridge windows to
request resources.  Several others don't request the window resources at
all.

Add a devm_request_pci_bus_resources() interface to make it easier for
drivers to request all the window resources.  Export to GPL modules (from
Arnd Bergmann &lt;arnd@arndb.de&gt;).

Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Do not treat EPROBE_DEFER as device attach failure</title>
<updated>2016-05-02T18:49:11+00:00</updated>
<author>
<name>Lukas Wunner</name>
<email>lukas@wunner.de</email>
</author>
<published>2016-05-02T18:48:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9a2a5a638f8eb9c612a7a9af0afab93f506f6ba4'/>
<id>9a2a5a638f8eb9c612a7a9af0afab93f506f6ba4</id>
<content type='text'>
Linux 4.5 introduced a behavioral change in device probing during the
suspend process with commit 013c074f8642 ("PM / sleep: prohibit devices
probing during suspend/hibernation"): It defers device probing during the
entire suspend process, starting from the prepare phase and ending with the
complete phase.  A rule existed before that "we rely on subsystems not to
do any probing once a device is suspended" but it is enforced only now
(Alan Stern, https://lkml.org/lkml/2015/9/15/908).

This resulted in a WARN splat if a PCI device (e.g., Thunderbolt) is
plugged in while the system is asleep: Upon waking up, pciehp_resume()
discovers new devices in the resume phase and immediately tries to bind
them to a driver.  Since probing is now deferred, device_attach() returns
-EPROBE_DEFER, which provoked a WARN in pci_bus_add_device().

Linux 4.6-rc1 aggravates the situation with commit ab1a187bba5c ("PCI:
Check device_attach() return value always"): If device_attach() returns a
negative value, pci_bus_add_device() now removes the sysfs and procfs
entries for the device and pci_bus_add_devices() subsequently locks up with
a BUG.  Even with the BUG fixed we're still in trouble because the device
remains on the deferred probing list even though its sysfs and procfs
entries are gone and its children won't be added.

Fix by not interpreting -EPROBE_DEFER as failure.  The device will be
probed eventually (through device_unblock_probing() in dpm_complete()) and
there is proper locking in place to avoid races (e.g., if devices are
unplugged again und thus deleted from the system before deferred probing
happens, I have tested this).  Also, those functions which dereference
dev-&gt;driver (e.g. pci_pm_*()) do contain proper NULL pointer checks.  So it
seems safe to ignore -EPROBE_DEFER.

Fixes: ab1a187bba5c ("PCI: Check device_attach() return value always")
Signed-off-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Cc: Grygorii Strashko &lt;grygorii.strashko@ti.com&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Linux 4.5 introduced a behavioral change in device probing during the
suspend process with commit 013c074f8642 ("PM / sleep: prohibit devices
probing during suspend/hibernation"): It defers device probing during the
entire suspend process, starting from the prepare phase and ending with the
complete phase.  A rule existed before that "we rely on subsystems not to
do any probing once a device is suspended" but it is enforced only now
(Alan Stern, https://lkml.org/lkml/2015/9/15/908).

This resulted in a WARN splat if a PCI device (e.g., Thunderbolt) is
plugged in while the system is asleep: Upon waking up, pciehp_resume()
discovers new devices in the resume phase and immediately tries to bind
them to a driver.  Since probing is now deferred, device_attach() returns
-EPROBE_DEFER, which provoked a WARN in pci_bus_add_device().

Linux 4.6-rc1 aggravates the situation with commit ab1a187bba5c ("PCI:
Check device_attach() return value always"): If device_attach() returns a
negative value, pci_bus_add_device() now removes the sysfs and procfs
entries for the device and pci_bus_add_devices() subsequently locks up with
a BUG.  Even with the BUG fixed we're still in trouble because the device
remains on the deferred probing list even though its sysfs and procfs
entries are gone and its children won't be added.

Fix by not interpreting -EPROBE_DEFER as failure.  The device will be
probed eventually (through device_unblock_probing() in dpm_complete()) and
there is proper locking in place to avoid races (e.g., if devices are
unplugged again und thus deleted from the system before deferred probing
happens, I have tested this).  Also, those functions which dereference
dev-&gt;driver (e.g. pci_pm_*()) do contain proper NULL pointer checks.  So it
seems safe to ignore -EPROBE_DEFER.

Fixes: ab1a187bba5c ("PCI: Check device_attach() return value always")
Signed-off-by: Lukas Wunner &lt;lukas@wunner.de&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Cc: Grygorii Strashko &lt;grygorii.strashko@ti.com&gt;
Cc: Alan Stern &lt;stern@rowland.harvard.edu&gt;</pre>
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