linux-stable.git/drivers/pci, branch v3.16.71 Linux kernel stable tree PCI: Add Device IDs for Intel GPU "spurious interrupt" quirk 2019-02-11T17:53:30+00:00 Bin Meng bmeng.cn@gmail.com 2018-09-26T15:14:01+00:00 8b0042e32aa6c02116e6892334ecf4c93dac54b6 commit d0c9606b31a21028fb5b753c8ad79626292accfd upstream. Add Device IDs to the Intel GPU "spurious interrupt" quirk table. For these devices, unplugging the VGA cable and plugging it in again causes spurious interrupts from the IGD. Linux eventually disables the interrupt, but of course that disables any other devices sharing the interrupt. The theory is that this is a VGA BIOS defect: it should have disabled the IGD interrupt but failed to do so. See f67fd55fa96f ("PCI: Add quirk for still enabled interrupts on Intel Sandy Bridge GPUs") and 7c82126a94e6 ("PCI: Add new ID for Intel GPU "spurious interrupt" quirk") for some history. [bhelgaas: See link below for discussion about how to fix this more generically instead of adding device IDs for every new Intel GPU. I hope this is the last patch to add device IDs.] Link: https://lore.kernel.org/linux-pci/1537974841-29928-1-git-send-email-bmeng.cn@gmail.com Signed-off-by: Bin Meng <bmeng.cn@gmail.com> [bhelgaas: changelog] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit d0c9606b31a21028fb5b753c8ad79626292accfd upstream.

Add Device IDs to the Intel GPU "spurious interrupt" quirk table.

For these devices, unplugging the VGA cable and plugging it in again causes
spurious interrupts from the IGD.  Linux eventually disables the interrupt,
but of course that disables any other devices sharing the interrupt.

The theory is that this is a VGA BIOS defect: it should have disabled the
IGD interrupt but failed to do so.

See f67fd55fa96f ("PCI: Add quirk for still enabled interrupts on Intel
Sandy Bridge GPUs") and 7c82126a94e6 ("PCI: Add new ID for Intel GPU
"spurious interrupt" quirk") for some history.

[bhelgaas: See link below for discussion about how to fix this more
generically instead of adding device IDs for every new Intel GPU.  I hope
this is the last patch to add device IDs.]

Link: https://lore.kernel.org/linux-pci/1537974841-29928-1-git-send-email-bmeng.cn@gmail.com
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI/ASPM: Fix link_state teardown on device removal 2019-02-11T17:53:20+00:00 Lukas Wunner lukas@wunner.de 2018-09-04T17:34:18+00:00 9439c89c7e771fae1533c02f257ef9befab0a0b8 commit aeae4f3e5c38d47bdaef50446dc0ec857307df68 upstream. Upon removal of the last device on a bus, the link_state of the bridge leading to that bus is sought to be torn down by having pci_stop_dev() call pcie_aspm_exit_link_state(). When ASPM was originally introduced by commit 7d715a6c1ae5 ("PCI: add PCI Express ASPM support"), it determined whether the device being removed is the last one by calling list_empty() on the bridge's subordinate devices list. That didn't work because the device is only removed from the list slightly later in pci_destroy_dev(). Commit 3419c75e15f8 ("PCI: properly clean up ASPM link state on device remove") attempted to fix it by calling list_is_last(), but that's not correct either because it checks whether the device is at the *end* of the list, not whether it's the last one *left* in the list. If the user removes the device which happens to be at the end of the list via sysfs but other devices are preceding the device in the list, the link_state is torn down prematurely. The real fix is to move the invocation of pcie_aspm_exit_link_state() to pci_destroy_dev() and reinstate the call to list_empty(). Remove a duplicate check for dev->bus->self because pcie_aspm_exit_link_state() already contains an identical check. Fixes: 7d715a6c1ae5 ("PCI: add PCI Express ASPM support") Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Shaohua Li <shaohua.li@intel.com> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit aeae4f3e5c38d47bdaef50446dc0ec857307df68 upstream.

Upon removal of the last device on a bus, the link_state of the bridge
leading to that bus is sought to be torn down by having pci_stop_dev()
call pcie_aspm_exit_link_state().

When ASPM was originally introduced by commit 7d715a6c1ae5 ("PCI: add
PCI Express ASPM support"), it determined whether the device being
removed is the last one by calling list_empty() on the bridge's
subordinate devices list.  That didn't work because the device is only
removed from the list slightly later in pci_destroy_dev().

Commit 3419c75e15f8 ("PCI: properly clean up ASPM link state on device
remove") attempted to fix it by calling list_is_last(), but that's not
correct either because it checks whether the device is at the *end* of
the list, not whether it's the last one *left* in the list.  If the user
removes the device which happens to be at the end of the list via sysfs
but other devices are preceding the device in the list, the link_state
is torn down prematurely.

The real fix is to move the invocation of pcie_aspm_exit_link_state() to
pci_destroy_dev() and reinstate the call to list_empty().  Remove a
duplicate check for dev->bus->self because pcie_aspm_exit_link_state()
already contains an identical check.

Fixes: 7d715a6c1ae5 ("PCI: add PCI Express ASPM support")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Shaohua Li <shaohua.li@intel.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: Reprogram bridge prefetch registers on resume 2018-12-16T22:09:28+00:00 Daniel Drake drake@endlessm.com 2018-09-27T20:47:33+00:00 d4f7913ccee18cde1a778a58c077e07e1d46fff1 commit 083874549fdfefa629dfa752785e20427dde1511 upstream. On 38+ Intel-based ASUS products, the NVIDIA GPU becomes unusable after S3 suspend/resume. The affected products include multiple generations of NVIDIA GPUs and Intel SoCs. After resume, nouveau logs many errors such as: fifo: fault 00 [READ] at 0000005555555000 engine 00 [GR] client 04 [HUB/FE] reason 4a [] on channel -1 [007fa91000 unknown] DRM: failed to idle channel 0 [DRM] Similarly, the NVIDIA proprietary driver also fails after resume (black screen, 100% CPU usage in Xorg process). We shipped a sample to NVIDIA for diagnosis, and their response indicated that it's a problem with the parent PCI bridge (on the Intel SoC), not the GPU. Runtime suspend/resume works fine, only S3 suspend is affected. We found a workaround: on resume, rewrite the Intel PCI bridge 'Prefetchable Base Upper 32 Bits' register (PCI_PREF_BASE_UPPER32). In the cases that I checked, this register has value 0 and we just have to rewrite that value. Linux already saves and restores PCI config space during suspend/resume, but this register was being skipped because upon resume, it already has value 0 (the correct, pre-suspend value). Intel appear to have previously acknowledged this behaviour and the requirement to rewrite this register: https://bugzilla.kernel.org/show_bug.cgi?id=116851#c23 Based on that, rewrite the prefetch register values even when that appears unnecessary. We have confirmed this solution on all the affected models we have in-hands (X542UQ, UX533FD, X530UN, V272UN). Additionally, this solves an issue where r8169 MSI-X interrupts were broken after S3 suspend/resume on ASUS X441UAR. This issue was recently worked around in commit 7bb05b85bc2d ("r8169: don't use MSI-X on RTL8106e"). It also fixes the same issue on RTL6186evl/8111evl on an Aimfor-tech laptop that we had not yet patched. I suspect it will also fix the issue that was worked around in commit 7c53a722459c ("r8169: don't use MSI-X on RTL8168g"). Thomas Martitz reports that this change also solves an issue where the AMD Radeon Polaris 10 GPU on the HP Zbook 14u G5 is unresponsive after S3 suspend/resume. Link: https://bugzilla.kernel.org/show_bug.cgi?id=201069 Signed-off-by: Daniel Drake <drake@endlessm.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-By: Peter Wu <peter@lekensteyn.nl> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 083874549fdfefa629dfa752785e20427dde1511 upstream.

On 38+ Intel-based ASUS products, the NVIDIA GPU becomes unusable after S3
suspend/resume.  The affected products include multiple generations of
NVIDIA GPUs and Intel SoCs.  After resume, nouveau logs many errors such
as:

  fifo: fault 00 [READ] at 0000005555555000 engine 00 [GR] client 04
        [HUB/FE] reason 4a [] on channel -1 [007fa91000 unknown]
  DRM: failed to idle channel 0 [DRM]

Similarly, the NVIDIA proprietary driver also fails after resume (black
screen, 100% CPU usage in Xorg process).  We shipped a sample to NVIDIA for
diagnosis, and their response indicated that it's a problem with the parent
PCI bridge (on the Intel SoC), not the GPU.

Runtime suspend/resume works fine, only S3 suspend is affected.

We found a workaround: on resume, rewrite the Intel PCI bridge
'Prefetchable Base Upper 32 Bits' register (PCI_PREF_BASE_UPPER32).  In the
cases that I checked, this register has value 0 and we just have to rewrite
that value.

Linux already saves and restores PCI config space during suspend/resume,
but this register was being skipped because upon resume, it already has
value 0 (the correct, pre-suspend value).

Intel appear to have previously acknowledged this behaviour and the
requirement to rewrite this register:
https://bugzilla.kernel.org/show_bug.cgi?id=116851#c23

Based on that, rewrite the prefetch register values even when that appears
unnecessary.

We have confirmed this solution on all the affected models we have in-hands
(X542UQ, UX533FD, X530UN, V272UN).

Additionally, this solves an issue where r8169 MSI-X interrupts were broken
after S3 suspend/resume on ASUS X441UAR.  This issue was recently worked
around in commit 7bb05b85bc2d ("r8169: don't use MSI-X on RTL8106e").  It
also fixes the same issue on RTL6186evl/8111evl on an Aimfor-tech laptop
that we had not yet patched.  I suspect it will also fix the issue that was
worked around in commit 7c53a722459c ("r8169: don't use MSI-X on
RTL8168g").

Thomas Martitz reports that this change also solves an issue where the AMD
Radeon Polaris 10 GPU on the HP Zbook 14u G5 is unresponsive after S3
suspend/resume.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=201069
Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-By: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: mvebu: Fix I/O space end address calculation 2018-12-16T22:08:40+00:00 Thomas Petazzoni thomas.petazzoni@bootlin.com 2018-08-03T14:38:44+00:00 fa7328b080f9eb446fcfde4a3d6cb17425cc9172 commit dfd0309fd7b30a5baffaf47b2fccb88b46d64d69 upstream. pcie->realio.end should be the address of last byte of the area, therefore using resource_size() of another resource is not correct, we must substract 1 to get the address of the last byte. Fixes: 11be65472a427 ("PCI: mvebu: Adapt to the new device tree layout") Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> [bwh: Backported to 3.16: adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit dfd0309fd7b30a5baffaf47b2fccb88b46d64d69 upstream.

pcie->realio.end should be the address of last byte of the area,
therefore using resource_size() of another resource is not correct, we
must substract 1 to get the address of the last byte.

Fixes: 11be65472a427 ("PCI: mvebu: Adapt to the new device tree layout")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: pciehp: Fix unprotected list iteration in IRQ handler 2018-12-16T22:08:19+00:00 Lukas Wunner lukas@wunner.de 2018-07-19T22:27:34+00:00 c28c5c78a887306c8d7cbe863766790bbfb13b2f commit 1204e35bedf4e5015cda559ed8c84789a6dae24e upstream. Commit b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device") iterates over the devices on a hotplug port's subordinate bus in pciehp's IRQ handler without acquiring pci_bus_sem. It is thus possible for a user to cause a crash by concurrently manipulating the device list, e.g. by disabling slot power via sysfs on a different CPU or by initiating a remove/rescan via sysfs. This can't be fixed by acquiring pci_bus_sem because it may sleep. The simplest fix is to avoid the list iteration altogether and just check the ignore_hotplug flag on the port itself. This works because pci_ignore_hotplug() sets the flag both on the device as well as on its parent bridge. We do lose the ability to print the name of the device blocking hotplug in the debug message, but that's probably bearable. Fixes: b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device") Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> [bwh: Backported to 3.16: s/events/intr_loc/] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 1204e35bedf4e5015cda559ed8c84789a6dae24e upstream.

Commit b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug
events for a device") iterates over the devices on a hotplug port's
subordinate bus in pciehp's IRQ handler without acquiring pci_bus_sem.
It is thus possible for a user to cause a crash by concurrently
manipulating the device list, e.g. by disabling slot power via sysfs
on a different CPU or by initiating a remove/rescan via sysfs.

This can't be fixed by acquiring pci_bus_sem because it may sleep.
The simplest fix is to avoid the list iteration altogether and just
check the ignore_hotplug flag on the port itself.  This works because
pci_ignore_hotplug() sets the flag both on the device as well as on its
parent bridge.

We do lose the ability to print the name of the device blocking hotplug
in the debug message, but that's probably bearable.

Fixes: b440bde74f04 ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[bwh: Backported to 3.16: s/events/intr_loc/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: pciehp: Fix use-after-free on unplug 2018-12-16T22:08:19+00:00 Lukas Wunner lukas@wunner.de 2018-07-19T22:27:32+00:00 848daaa8493f7501095d7099715d299a84d4e443 commit 281e878eab191cce4259abbbf1a0322e3adae02c upstream. When pciehp is unbound (e.g. on unplug of a Thunderbolt device), the hotplug_slot struct is deregistered and thus freed before freeing the IRQ. The IRQ handler and the work items it schedules print the slot name referenced from the freed structure in various informational and debug log messages, each time resulting in a quadruple dereference of freed pointers (hotplug_slot -> pci_slot -> kobject -> name). At best the slot name is logged as "(null)", at worst kernel memory is exposed in logs or the driver crashes: pciehp 0000:10:00.0:pcie204: Slot((null)): Card not present An attacker may provoke the bug by unplugging multiple devices on a Thunderbolt daisy chain at once. Unplugging can also be simulated by powering down slots via sysfs. The bug is particularly easy to trigger in poll mode. It has been present since the driver's introduction in 2004: https://git.kernel.org/tglx/history/c/c16b4b14d980 Fix by rearranging teardown such that the IRQ is freed first. Run the work items queued by the IRQ handler to completion before freeing the hotplug_slot struct by draining the work queue from the ->release_slot callback which is invoked by pci_hp_deregister(). Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 281e878eab191cce4259abbbf1a0322e3adae02c upstream.

When pciehp is unbound (e.g. on unplug of a Thunderbolt device), the
hotplug_slot struct is deregistered and thus freed before freeing the
IRQ.  The IRQ handler and the work items it schedules print the slot
name referenced from the freed structure in various informational and
debug log messages, each time resulting in a quadruple dereference of
freed pointers (hotplug_slot -> pci_slot -> kobject -> name).

At best the slot name is logged as "(null)", at worst kernel memory is
exposed in logs or the driver crashes:

  pciehp 0000:10:00.0:pcie204: Slot((null)): Card not present

An attacker may provoke the bug by unplugging multiple devices on a
Thunderbolt daisy chain at once.  Unplugging can also be simulated by
powering down slots via sysfs.  The bug is particularly easy to trigger
in poll mode.

It has been present since the driver's introduction in 2004:
https://git.kernel.org/tglx/history/c/c16b4b14d980

Fix by rearranging teardown such that the IRQ is freed first.  Run the
work items queued by the IRQ handler to completion before freeing the
hotplug_slot struct by draining the work queue from the ->release_slot
callback which is invoked by pci_hp_deregister().

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: hotplug: Don't leak pci_slot on registration failure 2018-12-16T22:08:18+00:00 Lukas Wunner lukas@wunner.de 2018-07-19T22:27:31+00:00 1fa3ed6898b12091e3dffaf591031031f9fec048 commit 4ce6435820d1f1cc2c2788e232735eb244bcc8a3 upstream. If addition of sysfs files fails on registration of a hotplug slot, the struct pci_slot as well as the entry in the slot_list is leaked. The issue has been present since the hotplug core was introduced in 2002: https://git.kernel.org/tglx/history/c/a8a2069f432c Perhaps the idea was that even though sysfs addition fails, the slot should still be usable. But that's not how drivers use the interface, they abort probe if a non-zero value is returned. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Greg Kroah-Hartman <greg@kroah.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 4ce6435820d1f1cc2c2788e232735eb244bcc8a3 upstream.

If addition of sysfs files fails on registration of a hotplug slot, the
struct pci_slot as well as the entry in the slot_list is leaked.  The
issue has been present since the hotplug core was introduced in 2002:
https://git.kernel.org/tglx/history/c/a8a2069f432c

Perhaps the idea was that even though sysfs addition fails, the slot
should still be usable.  But that's not how drivers use the interface,
they abort probe if a non-zero value is returned.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: shpchp: Fix AMD POGO identification 2018-11-20T18:05:09+00:00 Bjorn Helgaas bhelgaas@google.com 2018-05-30T19:06:42+00:00 d67598ec188e82e056598f1da37610357981eed6 commit bed4e9cfab93a0f3d0144cb919820e6d5c40b8b1 upstream. The fix for an AMD POGO erratum related to SHPC incorrectly identified the device. The workaround should be applied only for AMD POGO devices, but it was instead applied to: - all AMD bridges, and - all devices from any vendor with device ID 0x7458 Fixes: 53044f357448 ("[PATCH] PCI Hotplug: shpchp: AMD POGO errata fix") Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit bed4e9cfab93a0f3d0144cb919820e6d5c40b8b1 upstream.

The fix for an AMD POGO erratum related to SHPC incorrectly identified the
device.  The workaround should be applied only for AMD POGO devices, but it
was instead applied to:

  - all AMD bridges, and
  - all devices from any vendor with device ID 0x7458

Fixes: 53044f357448 ("[PATCH] PCI Hotplug: shpchp: AMD POGO errata fix")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume 2018-11-20T18:05:01+00:00 Mika Westerberg mika.westerberg@linux.intel.com 2018-05-23T22:14:39+00:00 1474ad318dbe0d8c18e663b88845740c468eb31c commit 13c65840feab8109194f9490c9870587173cb29d upstream. After a suspend/resume cycle the Presence Detect or Data Link Layer Status Changed bits might be set. If we don't clear them those events will not fire anymore and nothing happens for instance when a device is now hot-unplugged. Fix this by clearing those bits in a newly introduced function pcie_reenable_notification(). This should be fine because immediately after, we check if the adapter is still present by reading directly from the status register. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 13c65840feab8109194f9490c9870587173cb29d upstream.

After a suspend/resume cycle the Presence Detect or Data Link Layer Status
Changed bits might be set.  If we don't clear them those events will not
fire anymore and nothing happens for instance when a device is now
hot-unplugged.

Fix this by clearing those bits in a newly introduced function
pcie_reenable_notification().  This should be fine because immediately
after, we check if the adapter is still present by reading directly from
the status register.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
PCI: ibmphp: Fix use-before-set in get_max_bus_speed() 2018-11-20T18:04:49+00:00 Dan Carpenter dan.carpenter@oracle.com 2018-04-19T10:05:49+00:00 9447dabf5ea263c3a34a8d7c9f4e7b56259a558f commit 4051f5ebb11c6ef4b0d3eac2fbbd187c070656c5 upstream. The "rc" variable is only initialized on the error path. The caller doesn't check the return but, if "rc" is non-zero, then this function is basically a no-op. Fixes: 3749c51ac6c1 ("PCI: Make current and maximum bus speeds part of the PCI core") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 4051f5ebb11c6ef4b0d3eac2fbbd187c070656c5 upstream.

The "rc" variable is only initialized on the error path.  The caller
doesn't check the return but, if "rc" is non-zero, then this function is
basically a no-op.

Fixes: 3749c51ac6c1 ("PCI: Make current and maximum bus speeds part of the PCI core")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>