Pull x86 fixes from Peter Anvin:
"There is a small EFI fix and a big power regression fix in this batch.
My queue also had a fix for downing a CPU when there are insufficient
number of IRQ vectors available, but I'm holding that one for now due
to recent bug reports"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/efi: Don't select EFI from certain special ACPI drivers
x86 idle: Repair large-server 50-watt idle-power regression
ACPI container devices require special hotplug handling, at least
on some systems, since generally user space needs to carry out
system-specific cleanup before it makes sense to offline devices in
the container. However, the current ACPI hotplug code for containers
first attempts to offline devices in the container and only then it
notifies user space of the container offline.
Moreover, after commit 202317a573 (ACPI / scan: Add acpi_device
objects for all device nodes in the namespace), ACPI device objects
representing containers are present as long as the ACPI namespace
nodes corresponding to them are present, which may be forever, even
if the container devices are physically detached from the system (the
return values of the corresponding _STA methods change in those
cases, but generally the namespace nodes themselves are still there).
Thus it is useful to introduce entities representing containers that
will go away during container hot-unplug.
The goal of this change is to address both the above issues.
The idea is to create a "companion" container system device for each
of the ACPI container device objects during the initial namespace
scan or on a hotplug event making the container present. That system
device will be unregistered on container removal. A new bus type
for container devices is added for this purpose, because device
offline and online operations need to be defined for them. The
online operation is a trivial function that is always successful
and the offline uses a callback pointed to by the container device's
offline member.
For ACPI containers that callback simply walks the list of ACPI
device objects right below the container object (its children) and
checks if all of their physical companion devices are offline. If
that's not the case, it returns -EBUSY and the container system
devivce cannot be put offline. Consequently, to put the container
system device offline, it is necessary to put all of the physical
devices depending on its ACPI companion object offline beforehand.
Container system devices created for ACPI container objects are
initially online. They are created by the container ACPI scan
handler whose hotplug.demand_offline flag is set. That causes
acpi_scan_hot_remove() to check if the companion container system
device is offline before attempting to remove an ACPI container or
any devices below it. If the check fails, a KOBJ_CHANGE uevent is
emitted for the container system device in question and user space
is expected to offline all devices below the container and the
container itself in response to it. Then, user space can finalize
the removal of the container with the help of its ACPI device
object's eject attribute in sysfs.
Tested-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a new ACPI hotplug profile flag, demand_offline, such that if
set for the given ACPI device object's scan handler, it will cause
acpi_scan_hot_remove() to check if that device object's physical
companions are offline upfront and fail the hot removal if that
is not the case.
That flag will be useful to overcome a problem with containers on
some system where they can only be hot-removed after some cleanup
operations carried out by user space, which needs to be notified
of the container hot-removal before the kernel attempts to offline
devices in the container. In those cases the current implementation
of acpi_scan_hot_remove() is not sufficient, because it first tries
to offline the devices in the container and only if that is
suffcessful it tries to offline the container itself. As a result,
the container hot-removal notification is not delivered to user space
at the right time.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cleanup the logic in ghes_handle_memory_failure(). While at it, add
proper PFN validity check for UC error and cleanup the code logic to
make it simpler and cleaner.
Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1385363701-12387-2-git-send-email-gong.chen@linux.intel.com
[ Boris: massage commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
We do use memcpy to avoid access alignment issues between firmware and
OS. Now we can use a better and standard way to avoid this issue. While
at it, simplify some variable names to avoid the 80 cols limit and
use structure assignment instead of unnecessary memcpy. No functional
changes.
Because ERST record id cache is implemented in memory to increase the
access speed via caching ERST content we can refrain from using memcpy
there too and use regular assignment instead.
Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
Cc: Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1387348249-20014-1-git-send-email-gong.chen@linux.intel.com
[ Boris: massage commit message a bit. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Currently SCI is employed to handle corrected errors - memory corrected
errors, more specifically but in fact SCI still can be used to handle
any errors, e.g. uncorrected or even fatal ones if enabled by the BIOS.
Enable logging for those kinds of errors too.
Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1385363701-12387-1-git-send-email-gong.chen@linux.intel.com
[ Boris: massage commit message, rename function arg. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Some pstore backing devices use on board flash as persistent
storage. These have limited numbers of write cycles so it
is a poor idea to use them from high frequency operations.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The BIOS on recent HP laptops behaves differently with Win8 OSI,
e.g. no backlight control and no rfkill are available. List them in
the blacklist as a workaround.
This patch tries to reduce the added items by matching "G1" suffix,
e.g. machines are named like "HP ProBook 430 G1".
References: https://bugzilla.novell.com/show_bug.cgi?id=856294
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Correct "**retyurn_value" to "**return_value".
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Commit 7ea6c6c1 ("Move cper.c from drivers/acpi/apei to
drivers/firmware/efi") results in CONFIG_EFI being enabled even
when the user doesn't want this. Since ACPI APEI used to build
fine without UEFI (and as far as I know also has no functional
depency on it), at least in that case using a reverse dependency
is wrong (and a straight one isn't needed).
Whether the same is true for ACPI_EXTLOG I don't know - if there
is a functional dependency, it should depend on EFI rather than
selecting it. It certainly has (currently) no build dependency.
Adjust Kconfig and build logic so that the bad dependency gets
avoided.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/52AF1EBC020000780010DBF9@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
People seem to delight in writing wrong and broken mwait idle routines;
collapse the lot.
This leaves mwait_play_dead() the sole remaining user of __mwait() and
new __mwait() users are probably doing it wrong.
Also remove __sti_mwait() as its unused.
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Jacob Jun Pan <jacob.jun.pan@linux.intel.com>
Cc: Mike Galbraith <bitbucket@online.de>
Cc: Len Brown <lenb@kernel.org>
Cc: Rui Zhang <rui.zhang@intel.com>
Acked-by: Rafael Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131212141654.616820819@infradead.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
In acpi_processor_resume(), the variable resumed_bm_rld is being
used without being initialized, so initialize it.
Signed-off-by: Al Stone <al.stone@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Adjust the order of disabling the EC GPE and removing its handler to
avoid unhandled events.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Button GPEs have been enabled in the acpi_wake_device_init() during
boot and the button driver enables them for the second time.
Consequently, it is necessary to do
# echo disable > /sys/firmware/acpi/interrupts/gpeXXX
twice in a row to disable those GPEs via sysfs. This patch is to
remove the GPE enabling code from the button driver to avoid the
problem.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When I added support for ACPI5 I made the assumption that
injected processor errors would just need to know the APICID,
memory errors just the address and mask, and PCIe errors just the
segment/bus/device/function. So I had the code check the type of injection
and multiplex the "param1" value appropriately.
This was not a good assumption :-(
There are injection scenarios where we need to specify more than one of
these items. E.g. injecting a cache error we need to specify an APICID
of the cpu that owns the cache, and also an address (so that we can trip
the error by accessing the address).
Add a "flags" file to give the user direct access to specify which items
are valid in the ACPI SET_ERROR_TYPE_WITH_ADDRESS structure. Also add
new files param3 and param4 to hold all these values.
For backwards compatability with old injection scripts we maintain the
old behaviour if flags remains set at zero (or is reset to 0).
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
eMCA has higher H/W event reporting priority. Once it is
loaded, EDAC event reporting should be disabled, unless EDAC
overrides eMCA priority via command line parameter "edac_report=force".
Signed-off-by: Chen, Gong <gong.chen@linux.intel.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1386310630-12529-4-git-send-email-gong.chen@linux.intel.com
[ Boris: massage printk message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Use ACPI_COMPANION() to get an ACPI device instead of
acpi_bus_get_device() in the processor driver.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Correct "coolign" to "cooling" and "*_ptg" to "*_pctg" as intended.
This changes comment text only.
Signed-off-by: Al Stone <al.stone@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
acpi_sleep_init() is only called from acpi_bus_init() and the
code logic shows that it doesn't need to check acpi_disabled:
acpi_init();
if (acpi_disabled) return;
acpi_bus_init();
acpi_sleep_init();
if (acpi_disabled)
return 0;
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
acpi_dock_init() is only called from acpi_scan_init() and the
code logic shows that it doesn't need to check acpi_disabled:
acpi_init();
if (acpi_disabled) return;
acpi_scan_init();
acpi_dock_init();
if (acpi_disabled) /* redundant */
return;
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After commit 7f8f97c3cc (ACPI: acpi_table_parse() now returns
success/fail, not count), acpi_table_parse() returns '1' when it is
unable to find the table, but it should return a negative error code
in that case. Make it return -ENODEV instead.
Fix the same problem in acpi_table_init() analogously.
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Minor cleanup: remove some extra trailing white space.
Signed-off-by: Al Stone <al.stone@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To avoid build problems and breaking dependencies between ACPI header
files, <acpi/acpi.h> should not be included directly by code outside
of the ACPI core subsystem. However, that is possible if
<linux/acpi_io.h> is included, because that file contains
a direct inclusion of <acpi/acpi.h>.
For this reason, remove the direct <acpi/acpi.h> inclusion from
<linux/acpi_io.h>, move that file from include/linux/ to include/acpi/
and make <linux/acpi.h> include it for CONFIG_ACPI set along with the
other ACPI header files. Accordingly, Remove the inclusions of
<linux/acpi_io.h> from everywhere.
Of course, that causes the contents of the new <acpi/acpi_io.h> file
to be available for CONFIG_ACPI set only, so intel_opregion.o that
depends on it should also depend on CONFIG_ACPI (and it really should
not be compiled for CONFIG_ACPI unset anyway).
References: https://01.org/linuxgraphics/sites/default/files/documentation/acpi_igd_opregion_spec.pdf
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since drivers/acpi/nvs.c includes <linux/acpi.h> and is only compiled
for CONFIG_ACPI set, it doesn't need to include <acpi/acpiosxf.h>
directly, which is formally incorrect. Remove the <acpi/acpiosxf.h>
inclusion from that file.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since drivers/ide/ide-acpi.c is the only remaining user of
acpi_get_child(), move that function into that file as a static
routine.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There is no reason to pass an ACPI handle to acpi_bind_one() instead
of a struct acpi_device pointer to the target device object, so
modify that function to take a struct acpi_device pointer as its
second argument and update all code depending on it accordingly.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Lan Tianyu <tianyu.lan@intel.com> # for USB/ACPI
Replace the .find_device function pointer in struct acpi_bus_type
with a new one, .find_companion, that is supposed to point to a
function returning struct acpi_device pointer (instead of an int)
and takes one argument (instead of two). This way the role of
this callback is more clear and the implementation of it can
be more straightforward.
Update all of the users of struct acpi_bus_type (PCI, PNP/ACPI and
USB) to reflect the structure change.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Lan Tianyu <tianyu.lan@intel.com> # for USB/ACPI
Modify acpi_preset_companion() to take a struct acpi_device pointer
instead of an ACPI handle as its second argument and redefine it as
a static inline wrapper around ACPI_COMPANION_SET() passing the
return value of acpi_find_child_device() directly as the second
argument to it. Update its users to pass struct acpi_device
pointers instead of ACPI handles to it.
This allows some unnecessary acpi_bus_get_device() calls to be
avoided.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Tested-by: Aaron Lu <aaron.lu@intel.com> # for ATA binding
Since acpi_get_child() is the only user of acpi_find_child() now,
drop the static inline definition of the former and redefine the
latter as new acpi_get_child().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Tested-by: Aaron Lu <aaron.lu@intel.com> # for ATA binding
It is much more efficient to use acpi_find_child_device()
for child devices lookup in acpi_pci_find_device() and pass
ACPI_COMPANION(dev->parent) to it directly instead of obtaining
ACPI_HANDLE() of ACPI_COMPANION(dev->parent) and passing it to
acpi_find_child() which has to run acpi_bus_get_device() to
obtain ACPI_COMPANION(dev->parent) from that again.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Now that we create a struct acpi_device object for every ACPI
namespace node representing a device, it is not necessary to
use acpi_walk_namespace() for child device lookup in
acpi_find_child() any more. Instead, we can simply walk the
list of children of the given struct acpi_device object and
return the matching one (or the one which is the best match if
there are more of them). The checks done during the matching
loop can be simplified too so that the secondary namespace walks
in find_child_checks() are not necessary any more.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Replace direct inclusions of <acpi/acpi.h>, <acpi/acpi_bus.h> and
<acpi/acpi_drivers.h>, which are incorrect, with <linux/acpi.h>
inclusions and remove some inclusions of those files that aren't
necessary.
First of all, <acpi/acpi.h>, <acpi/acpi_bus.h> and <acpi/acpi_drivers.h>
should not be included directly from any files that are built for
CONFIG_ACPI unset, because that generally leads to build warnings about
undefined symbols in !CONFIG_ACPI builds. For CONFIG_ACPI set,
<linux/acpi.h> includes those files and for CONFIG_ACPI unset it
provides stub ACPI symbols to be used in that case.
Second, there are ordering dependencies between those files that always
have to be met. Namely, it is required that <acpi/acpi_bus.h> be included
prior to <acpi/acpi_drivers.h> so that the acpi_pci_root declarations the
latter depends on are always there. And <acpi/acpi.h> which provides
basic ACPICA type declarations should always be included prior to any other
ACPI headers in CONFIG_ACPI builds. That also is taken care of including
<linux/acpi.h> as appropriate.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> (drivers/pci stuff)
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> (Xen stuff)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This adds the new ACPI ID (INT33FC) for the BayTrail GPIO
banks as seen on a BayTrail M System-On-Chip platform. This
ACPI ID is used by the BayTrail GPIO (pinctrl) driver to
manage the Low Power Subsystem (LPSS).
Signed-off-by: Paul Drews <paul.drews@intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* acpica:
ACPI: Clean up incorrect inclusions of ACPICA headers
ACPICA: Update version to 20131115.
ACPICA: Add support to delete all objects attached to the root namespace node.
ACPICA: Delete all attached data objects during namespace node deletion.
ACPICA: Resources: Fix loop termination for the get AML length function.
ACPICA: Tests: Add CHECKSUM_ABORT protection for test utilities.
ACPICA: Debug output: Do not emit function nesting level for kernel build.
Header file <acpi/acpi.h> contains environemnt settings and architecture
specific implementation that should be included before any other ACPICA
headers in order to keep a consistent build environment for ACPICA users.
The following internal ACPICA header files should be included from
<acpi/acpi.h> and should not be included by other kernel files:
<acpi/acpiosxf.h>
<acpi/acpixf.h>
Clean up incorrect inclusions of these files from non-ACPICA source
files.
[rjw: Subject and changelog]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Rework acpi_bus_trim() and acpi_bus_device_attach(), which is
renamed as acpi_bus_attach(), to walk the list of each device
object's children directly and call themselves recursively for
each child instead of using acpi_walk_namespace(). This
simplifies the code quite a bit and avoids the overhead of
callbacks and the ACPICA's internal processing which are not
really necessary for these two routines.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Introduce a static inline function for setting the status field
of struct acpi_device on the basis of a supplied u32 number,
acpi_set_device_status(), and use it instead of the horrible
horrible STRUCT_TO_INT() macro wherever applicable. Having done
that, drop STRUCT_TO_INT() (and pretend that it has never existed).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
There are two global hotplug notification handling routines in bus.c,
acpi_bus_check_device() and acpi_bus_check_scope(), that have never
been finished and don't do anything useful, so drop them.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The generic ACPI hotplug code used for several types of device
doesn't handle surprise removals, mostly because those devices
currently cannot be removed by surprise in the majority of systems.
However, surprise removals should be handled by that code as well
as surprise additions of devices, so make it do that.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Move container-specific uevents from the core hotplug code to the
container scan handler's .attach() and .detach() callbacks.
This way the core will not have to special-case containers and
the uevents will be guaranteed to happen every time a container
is either scanned or trimmed as appropriate.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Rework the common ACPI device hotplug code so that it is suitable
for PCI host bridge hotplug and switch the PCI host bridge scan
handler to using the common hotplug code.
This allows quite a few lines of code that are not necessary any more
to be dropped from the PCI host bridge scan handler and removes
arbitrary differences in behavior between PCI host bridge hotplug
and ACPI-based hotplug of other components, like CPUs and memory.
Also acpi_device_hotplug() can be static now.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Modify the common ACPI device hotplug code to always queue up the
same function, acpi_device_hotplug(), using acpi_hotplug_execute()
and make the PCI host bridge hotplug code use that function too for
device hot removal.
This allows some code duplication to be reduced and a race condition
where the relevant ACPI handle may become invalid between the
notification handler and the function queued up by it via
acpi_hotplug_execute() to be avoided.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
If the scan handler for the given device has hotplug.enabled
unset, it doesn't really make sense to fail bus check and device
check notifications.
First, bus check may not have anything to do with the device it is
signaled for, but it may concern another device on the bus below
this one. For this reason, bus check notifications should not be
failed if hotplug is disabled for the target device.
Second, device check notifications are signaled only after a device
has already appeared (or disappeared), so failing it can only prevent
scan handlers and drivers from attaching to that (already existing)
device, which is not very useful.
Consequently, if device hotplug is disabled through the device's
scan handler, fail eject request notifications only.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Modify the ACPI namespace scanning code to register a struct
acpi_device object for every namespace node representing a device,
processor and so on, even if the device represented by that namespace
node is reported to be not present and not functional by _STA.
There are multiple reasons to do that. First of all, it avoids
quite a lot of overhead when struct acpi_device objects are
deleted every time acpi_bus_trim() is run and then added again
by a subsequent acpi_bus_scan() for the same scope, although the
namespace objects they correspond to stay in memory all the time
(which always is the case on a vast majority of systems).
Second, it will allow user space to see that there are namespace
nodes representing devices that are not present at the moment and may
be added to the system. It will also allow user space to evaluate
_SUN for those nodes to check what physical slots the "missing"
devices may be put into and it will make sense to add a sysfs
attribute for _STA evaluation after this change (that will be
useful for thermal management on some systems).
Next, it will help to consolidate the ACPI hotplug handling among
subsystems by making it possible to store hotplug-related information
in struct acpi_device objects in a standard common way.
Finally, it will help to avoid a race condition related to the
deletion of ACPI namespace nodes. Namely, namespace nodes may be
deleted as a result of a table unload triggered by _EJ0 or _DCK.
If a hotplug notification for one of those nodes is triggered
right before the deletion and it executes a hotplug callback
via acpi_hotplug_execute(), the ACPI handle passed to that
callback may be stale when the callback actually runs. One way
to work around that is to always pass struct acpi_device pointers
to hotplug callbacks after doing a get_device() on the objects in
question which eliminates the use-after-free possibility (the ACPI
handles in those objects are invalidated by acpi_scan_drop_device(),
so they will trigger ACPICA errors on attempts to use them).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
If an ACPI namespace node is removed (usually, as a result of a
table unload), and there is a data object attached to that node,
acpi_ns_delete_node() executes the removal handler submitted to
acpi_attach_data() for that object. That handler is currently empty
for struct acpi_device objects, so it is necessary to detach those
objects from the corresponding ACPI namespace nodes in advance every
time a table unload may happen. That is cumbersome and inefficient
and leads to some design constraints that turn out to be quite
inconvenient (in particular, struct acpi_device objects cannot be
registered for namespace nodes representing devices that are not
reported as present or functional by _STA).
For this reason, introduce a non-empty removal handler for ACPI
device objects that will unregister them when their ACPI namespace
nodes go away.
This code modification alone should not change functionality except
for the ordering of the ACPI hotplug workqueue which should not
matter (without subsequent code changes).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
