The PCI spec indicates that with stable power, reset needs to be
asserted for a minimum of 1ms (Trst). We should be able to assume
stable power for a Hot Reset, but we add another millisecond as
a fudge factor to make sure the reset is seen on the bus for at least
a full 1ms.
After reset is de-asserted we must wait for devices to complete
initialization. The specs refer to this as "recovery time" (Trhfa).
For PCI this is 2^25 clock cycles or 2^26 for PCI-X. For minimum
bus speeds, both of those come to 1s. PCIe "softens" this
requirement with the Configuration Request Retry Status (CRS)
completion status. Theoretically we could use CRS to shorten the
wait time. We don't make use of that here, using a fixed 1s delay
to allow devices to re-initialize.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Devices come out of reset in D0. Restoring a device to a different
post-reset state takes more smarts than our simple config space
restore, which can leave devices in an inconsistent state. For
example, if a device is reset in D3, but the restore doesn't
successfully return the device to D3, then the actual state of the
device and dev->current_state are contradictory. Put everything
in D0 going into the reset, then we don't need to do anything
special on the way out.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Sometimes pci_reset_function() is not sufficient. We have cases where
devices do not support any kind of reset, but there might be multiple
functions on the bus preventing pci_reset_function() from doing a
secondary bus reset. We also have cases where a device will advertise
that it supports a PM reset, but really does nothing on D3hot->D0
(graphics cards are notorious for this). These devices often also
have more than one function, so even blacklisting PM reset for them
wouldn't allow a secondary bus reset through pci_reset_function().
If a driver supports multiple devices it should have the ability to
induce a bus reset when it needs to. This patch provides that ability
through pci_reset_slot() and pci_reset_bus(). It's the caller's
responsibility when using these interfaces to understand that all of
the devices in or below the slot (or on or below the bus) will be
reset and therefore should be under control of the caller. PCI state
of all the affected devices is saved and restored around these resets,
but internal state of all of the affected devices is reset (which
should be the intention).
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Only cosmetic code changes to existing paths. Expand the comment in
the new pci_dev_save_and_disable() function since there's a lot
hidden in that Command register write.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
If the hotplug controller provides a way to reset a slot, use that
before a direct parent bus reset. Like the bus reset option, this is
only available when a single pci_dev occupies the slot.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
PCIe hotplug has a bus per slot, so we can just use a normal
secondary bus reset. However, if a slot supports surprise removal,
a bus reset can be seen as a presence detection change triggering
a hot-remove followed by a hot-add. Disable presence detection from
triggering an interrupt or being polled around the bus reset.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This optional callback allows hotplug controllers to perform slot
specific resets. These may be necessary in cases where a normal
secondary bus reset can interact with controller logic and expose
spurious hotplugs.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Move the secondary bus reset code from pci_parent_bus_reset() into its own
function. Export it as we'll later be calling it from hotplug controllers
and elsewhere.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Pull ACPI video support fixes from Rafael Wysocki:
"I'm sending a separate pull request for this as it may be somewhat
controversial. The breakage addressed here is not really new and the
fixes may not satisfy all users of the affected systems, but we've had
so much back and forth dance in this area over the last several weeks
that I think it's time to actually make some progress.
The source of the problem is that about a year ago we started to tell
BIOSes that we're compatible with Windows 8, which we really need to
do, because some systems shipping with Windows 8 are tested with it
and nothing else, so if we tell their BIOSes that we aren't compatible
with Windows 8, we expose our users to untested BIOS/AML code paths.
However, as it turns out, some Windows 8-specific AML code paths are
not tested either, because Windows 8 actually doesn't use the ACPI
methods containing them, so if we declare Windows 8 compatibility and
attempt to use those ACPI methods, things break. That occurs mostly
in the backlight support area where in particular the _BCM and _BQC
methods are plain unusable on some systems if the OS declares Windows
8 compatibility.
[ The additional twist is that they actually become usable if the OS
says it is not compatible with Windows 8, but that may cause
problems to show up elsewhere ]
Investigation carried out by Matthew Garrett indicates that what
Windows 8 does about backlight is to leave backlight control up to
individual graphics drivers. At least there's evidence that it does
that if the Intel graphics driver is used, so we've decided to follow
Windows 8 in that respect and allow i915 to control backlight (Daniel
likes that part).
The first commit from Aaron Lu makes ACPICA export the variable from
which we can infer whether or not the BIOS believes that we are
compatible with Windows 8.
The second commit from Matthew Garrett prepares the ACPI video driver
by making it initialize the ACPI backlight even if it is not going to
be used afterward (that is needed for backlight control to work on
Thinkpads).
The third commit implements the actual workaround making i915 take
over backlight control if the firmware thinks it's dealing with
Windows 8 and is based on the work of multiple developers, including
Matthew Garrett, Chun-Yi Lee, Seth Forshee, and Aaron Lu.
The final commit from Aaron Lu makes us follow Windows 8 by informing
the firmware through the _DOS method that it should not carry out
automatic brightness changes, so that brightness can be controlled by
GUI.
Hopefully, this approach will allow us to avoid using blacklists of
systems that should not declare Windows 8 compatibility just to avoid
backlight control problems in the future.
- Change from Aaron Lu makes ACPICA export a variable which can be
used by driver code to determine whether or not the BIOS believes
that we are compatible with Windows 8.
- Change from Matthew Garrett makes the ACPI video driver initialize
the ACPI backlight even if it is not going to be used afterward
(that is needed for backlight control to work on Thinkpads).
- Fix from Rafael J Wysocki implements Windows 8 backlight support
workaround making i915 take over bakclight control if the firmware
thinks it's dealing with Windows 8. Based on the work of multiple
developers including Matthew Garrett, Chun-Yi Lee, Seth Forshee,
and Aaron Lu.
- Fix from Aaron Lu makes the kernel follow Windows 8 by informing
the firmware through the _DOS method that it should not carry out
automatic brightness changes, so that brightness can be controlled
by GUI"
* tag 'acpi-video-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI / video: no automatic brightness changes by win8-compatible firmware
ACPI / video / i915: No ACPI backlight if firmware expects Windows 8
ACPI / video: Always call acpi_video_init_brightness() on init
ACPICA: expose OSI version
Pull ext[34] tmpfile bugfix from Ted Ts'o:
"Fix regression caused by commit af51a2ac36 which added ->tmpfile()
support (along with a similar fix for ext3)"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext3: fix a BUG when opening a file with O_TMPFILE flag
ext4: fix a BUG when opening a file with O_TMPFILE flag
Pull staging tree fixes from Greg KH:
"Here are a few iio driver fixes for 3.11-rc2. They are still spread
across drivers/iio and drivers/staging/iio so they are coming in
through this tree.
I've also removed the drivers/staging/csr/ driver as the developers
who originally sent it to me have moved on to other companies, and CSR
still will not send us the specs for the device, making the driver
pretty much obsolete and impossible to fix up. Deleting it now
prevents people from sending in lots of tiny codingsyle fixes that
will never go anywhere.
It also helps to offset the large lustre filesystem merge that
happened in 3.11-rc1 in the overall 3.11.0 diffstat. :)"
* tag 'staging-3.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: csr: remove driver
iio: lps331ap: Fix wrong in_pressure_scale output value
iio staging: fix lis3l02dq, read error handling
staging:iio:ad7291: add missing .driver_module to struct iio_info
iio: ti_am335x_adc: add missing .driver_module to struct iio_info
iio: mxs-lradc: Remove useless check in read_raw
iio: mxs-lradc: Fix misuse of iio->trig
iio: inkern: fix iio_convert_raw_to_processed_unlocked
iio: Fix iio_channel_has_info
iio:trigger: device_unregister->device_del to avoid double free
iio: dac: ad7303: fix error return code in ad7303_probe()
Pull vfs fixes from Al Viro:
"The sget() one is a long-standing bug and will need to go into -stable
(in fact, it had been originally caught in RHEL6), the other two are
3.11-only"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: constify dentry parameter in d_count()
livelock avoidance in sget()
allow O_TMPFILE to work with O_WRONLY
Pull ext4 bugfixes from Ted Ts'o:
"Fixes for 3.11-rc2, sent at 5pm, in the professoinal style. :-)"
I'm not sure I like this new level of "professionalism".
9-5, people, 9-5.
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: call ext4_es_lru_add() after handling cache miss
ext4: yield during large unlinks
ext4: make the extent_status code more robust against ENOMEM failures
ext4: simplify calculation of blocks to free on error
ext4: fix error handling in ext4_ext_truncate()
Pull NFS client bugfixes from Trond Myklebust:
- Fix a regression against NFSv4 FreeBSD servers when creating a new
file
- Fix another regression in rpc_client_register()
* tag 'nfs-for-3.11-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
NFSv4: Fix a regression against the FreeBSD server
SUNRPC: Fix another issue with rpc_client_register()
Pull btrfs fixes from Josef Bacik:
"I'm playing the role of Chris Mason this week while he's on vacation.
There are a few critical fixes for btrfs here, all regressions and
have been tested well"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next:
Btrfs: fix wrong write offset when replacing a device
Btrfs: re-add root to dead root list if we stop dropping it
Btrfs: fix lock leak when resuming snapshot deletion
Btrfs: update drop progress before stopping snapshot dropping
so that it can be used in places like d_compare/d_hash
without causing a compiler warning.
Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Eric Sandeen has found a nasty livelock in sget() - take a mount(2) about
to fail. The superblock is on ->fs_supers, ->s_umount is held exclusive,
->s_active is 1. Along comes two more processes, trying to mount the same
thing; sget() in each is picking that superblock, bumping ->s_count and
trying to grab ->s_umount. ->s_active is 3 now. Original mount(2)
finally gets to deactivate_locked_super() on failure; ->s_active is 2,
superblock is still ->fs_supers because shutdown will *not* happen until
->s_active hits 0. ->s_umount is dropped and now we have two processes
chasing each other:
s_active = 2, A acquired ->s_umount, B blocked
A sees that the damn thing is stillborn, does deactivate_locked_super()
s_active = 1, A drops ->s_umount, B gets it
A restarts the search and finds the same superblock. And bumps it ->s_active.
s_active = 2, B holds ->s_umount, A blocked on trying to get it
... and we are in the earlier situation with A and B switched places.
The root cause, of course, is that ->s_active should not grow until we'd
got MS_BORN. Then failing ->mount() will have deactivate_locked_super()
shut the damn thing down. Fortunately, it's easy to do - the key point
is that grab_super() is called only for superblocks currently on ->fs_supers,
so it can bump ->s_count and grab ->s_umount first, then check MS_BORN and
bump ->s_active; we must never increment ->s_count for superblocks past
->kill_sb(), but grab_super() is never called for those.
The bug is pretty old; we would've caught it by now, if not for accidental
exclusion between sget() for block filesystems; the things like cgroup or
e.g. mtd-based filesystems don't have anything of that sort, so they get
bitten. The right way to deal with that is obviously to fix sget()...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull UML fixes from Richard Weinberger:
"Special thanks goes to Toralf Föster for continuously testing UML and
reporting issues!"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: remove dead code
um: siginfo cleanup
uml: Fix which_tmpdir failure when /dev/shm is a symlink, and in other edge cases
um: Fix wait_stub_done() error handling
um: Mark stub pages mapping with VM_PFNMAP
um: Fix return value of strnlen_user()
Pull MIPS fixes from Ralf Baechle:
"MIPS fixes for 3.11. Half of then is for Netlogic the remainder
touches things across arch/mips.
Nothing really dramatic and by rc1 standards MIPS will be in fairly
good shape with this applied. Tested by building all MIPS defconfigs
of which with this pull request four platforms won't build. And yes,
it boots also on my favorite test systems"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
MIPS: kvm: Kconfig: Drop HAVE_KVM dependency from VIRTUALIZATION
MIPS: Octeon: Fix DT pruning bug with pip ports
MIPS: KVM: Mark KVM_GUEST (T&E KVM) as BROKEN_ON_SMP
MIPS: tlbex: fix broken build in v3.11-rc1
MIPS: Netlogic: Add XLP PIC irqdomain
MIPS: Netlogic: Fix USB block's coherent DMA mask
MIPS: tlbex: Fix typo in r3000 tlb store handler
MIPS: BMIPS: Fix thinko to release slave TP from reset
MIPS: Delete dead invocation of exception_exit().
Pull arm64 fixes from Catalin Marinas:
- Post -rc1 update to the common reboot infrastructure.
- Fixes (user cache maintenance fault handling, !COMPAT compilation,
CPU online and interrupt hanlding).
* tag 'arm64-stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64:
arm64: use common reboot infrastructure
arm64: mm: don't treat user cache maintenance faults as writes
arm64: add '#ifdef CONFIG_COMPAT' for aarch32_break_handler()
arm64: Only enable local interrupts after the CPU is marked online
Alex Williamson
Linus Torvalds
Zheng Liu
Peng Tao
Al Viro