<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/acpi, branch v2.6.38.6</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>ACPI / PM: Avoid infinite recurrence while registering power resources</title>
<updated>2011-05-02T16:19:43+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2011-04-26T09:33:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2aaf1f781cb77812e5d9678d7b126ec13cebf283'/>
<id>2aaf1f781cb77812e5d9678d7b126ec13cebf283</id>
<content type='text'>
commit 7bed50c5edf5cba8dd515a31191cbfb6065ddc85 upstream.

There is at least one BIOS with a DSDT containing a power resource
object with a _PR0 entry pointing back to that power resource.  In
consequence, while registering that power resource
acpi_bus_get_power_flags() sees that it depends on itself and tries
to register it again, which leads to an infinitely deep recurrence.
This problem was introduced by commit bf325f9538d8c89312be305b9779e
(ACPI / PM: Register power resource devices as soon as they are
needed).

To fix this problem use the observation that power resources cannot
be power manageable and prevent acpi_bus_get_power_flags() from
being called for power resource objects.

References: https://bugzilla.kernel.org/show_bug.cgi?id=31872
Reported-and-tested-by: Pascal Dormeau &lt;pdormeau@free.fr&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Acked-by: Len Brown &lt;lenb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7bed50c5edf5cba8dd515a31191cbfb6065ddc85 upstream.

There is at least one BIOS with a DSDT containing a power resource
object with a _PR0 entry pointing back to that power resource.  In
consequence, while registering that power resource
acpi_bus_get_power_flags() sees that it depends on itself and tries
to register it again, which leads to an infinitely deep recurrence.
This problem was introduced by commit bf325f9538d8c89312be305b9779e
(ACPI / PM: Register power resource devices as soon as they are
needed).

To fix this problem use the observation that power resources cannot
be power manageable and prevent acpi_bus_get_power_flags() from
being called for power resource objects.

References: https://bugzilla.kernel.org/show_bug.cgi?id=31872
Reported-and-tested-by: Pascal Dormeau &lt;pdormeau@free.fr&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Acked-by: Len Brown &lt;lenb@kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI battery: fribble sysfs files from a resume notifier</title>
<updated>2011-05-02T16:19:41+00:00</updated>
<author>
<name>Kyle McMartin</name>
<email>kyle@redhat.com</email>
</author>
<published>2011-03-22T20:19:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=36d08a041f93f2c5370f95f9611c9065bb79e4fb'/>
<id>36d08a041f93f2c5370f95f9611c9065bb79e4fb</id>
<content type='text'>
commit 25be5821521640eb00b7eb219ffe59664510d073 upstream.

Commit da8aeb92 re-poked the battery on resume, but Linus reports that
it broke his eee and partially reverted it in b23fffd7. Unfortunately
this also results in my x201s giving crack values until the sysfs files
are poked again. In the revert message, it was suggested that we poke it
from a PM notifier, so let's do that.

With this in place, I haven't noticed the units going nutty on my
gnome-power-manager across a dozen suspends or so...

Signed-off-by: Kyle McMartin &lt;kyle@redhat.com&gt;
Acked-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Len Brown &lt;len.brown@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 25be5821521640eb00b7eb219ffe59664510d073 upstream.

Commit da8aeb92 re-poked the battery on resume, but Linus reports that
it broke his eee and partially reverted it in b23fffd7. Unfortunately
this also results in my x201s giving crack values until the sysfs files
are poked again. In the revert message, it was suggested that we poke it
from a PM notifier, so let's do that.

With this in place, I haven't noticed the units going nutty on my
gnome-power-manager across a dozen suspends or so...

Signed-off-by: Kyle McMartin &lt;kyle@redhat.com&gt;
Acked-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Len Brown &lt;len.brown@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>PCI/ACPI: Report ASPM support to BIOS if not disabled from command line</title>
<updated>2011-04-14T20:02:00+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2011-03-05T12:21:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2e8baeac894365899a6934987bf2dfc6a28d4dd6'/>
<id>2e8baeac894365899a6934987bf2dfc6a28d4dd6</id>
<content type='text'>
commit 8b8bae901ce23addbdcdb54fa1696fb2d049feb5 upstream.

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.

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 &lt;odi@odi.ch&gt;
Reviewed-by: Kenji Kaneshige &lt;kaneshige.kenji@jp.fujitsu.com&gt;
Tested-by: Kenji Kaneshige &lt;kaneshige.kenji@jp.fujitsu.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8b8bae901ce23addbdcdb54fa1696fb2d049feb5 upstream.

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.

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 &lt;odi@odi.ch&gt;
Reviewed-by: Kenji Kaneshige &lt;kaneshige.kenji@jp.fujitsu.com&gt;
Tested-by: Kenji Kaneshige &lt;kaneshige.kenji@jp.fujitsu.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Jesse Barnes &lt;jbarnes@virtuousgeek.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@suse.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / ACPICA: Implicit notify for multiple devices</title>
<updated>2011-02-24T18:59:21+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2011-02-24T18:59:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=981858bd7a401aa9607d9f430d5de920025fc3ea'/>
<id>981858bd7a401aa9607d9f430d5de920025fc3ea</id>
<content type='text'>
Commit bba63a2 (ACPICA: Implicit notify support) introduced a
mechanism that causes a notify request of type
ACPI_NOTIFY_DEVICE_WAKE to be queued automatically by
acpi_ev_asynch_execute_gpe_method() for the device whose _PRW points
to the GPE being handled if that GPE is not associated with an
_Lxx/_Exx method.  However, it turns out that on some systems there
are multiple devices with _PRW pointing to the same GPE without
_Lxx/_Exx and the mechanism introduced by commit bba63a2 needs to be
extended so that "implicit" notify requests of type
ACPI_NOTIFY_DEVICE_WAKE can be queued automatically for all those
devices at the same time.

Reported-and-tested-by: Matthew Garrett &lt;mjg@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit bba63a2 (ACPICA: Implicit notify support) introduced a
mechanism that causes a notify request of type
ACPI_NOTIFY_DEVICE_WAKE to be queued automatically by
acpi_ev_asynch_execute_gpe_method() for the device whose _PRW points
to the GPE being handled if that GPE is not associated with an
_Lxx/_Exx method.  However, it turns out that on some systems there
are multiple devices with _PRW pointing to the same GPE without
_Lxx/_Exx and the mechanism introduced by commit bba63a2 needs to be
extended so that "implicit" notify requests of type
ACPI_NOTIFY_DEVICE_WAKE can be queued automatically for all those
devices at the same time.

Reported-and-tested-by: Matthew Garrett &lt;mjg@redhat.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / debugfs: Fix buffer overflows, double free</title>
<updated>2011-02-24T18:59:06+00:00</updated>
<author>
<name>Vasiliy Kulikov</name>
<email>segoon@openwall.com</email>
</author>
<published>2011-02-19T13:18:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2949ad50711cc161721cf788711722eeeca33764'/>
<id>2949ad50711cc161721cf788711722eeeca33764</id>
<content type='text'>
File position is not controlled, it may lead to overwrites of arbitrary
kernel memory.  Also the code may kfree() the same pointer multiple
times.

One more flaw is still present: if multiple processes open the file then
all 3 static variables are shared, leading to various race conditions.
They should be moved to file-&gt;private_data.

Signed-off-by: Vasiliy Kulikov &lt;segoon@openwall.com&gt;
Reviewed-by: WANG Cong &lt;xiyou.wangcong@gmail.com&gt;
Reviewed-by: Eugene Teo &lt;eugeneteo@kernel.org&gt;
Cc: stable@kernel.org
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
File position is not controlled, it may lead to overwrites of arbitrary
kernel memory.  Also the code may kfree() the same pointer multiple
times.

One more flaw is still present: if multiple processes open the file then
all 3 static variables are shared, leading to various race conditions.
They should be moved to file-&gt;private_data.

Signed-off-by: Vasiliy Kulikov &lt;segoon@openwall.com&gt;
Reviewed-by: WANG Cong &lt;xiyou.wangcong@gmail.com&gt;
Reviewed-by: Eugene Teo &lt;eugeneteo@kernel.org&gt;
Cc: stable@kernel.org
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'iomem' into release</title>
<updated>2011-02-15T20:25:48+00:00</updated>
<author>
<name>Len Brown</name>
<email>len.brown@intel.com</email>
</author>
<published>2011-02-15T20:25:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=dc3397437d740dd7ba5b8d1bf548b7288f564152'/>
<id>dc3397437d740dd7ba5b8d1bf548b7288f564152</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / Video: Probe for output switch method when searching video devices.</title>
<updated>2011-02-12T00:40:16+00:00</updated>
<author>
<name>Michael Karcher</name>
<email>kernel@mkarcher.dialup.fu-berlin.de</email>
</author>
<published>2011-02-12T00:40:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ed764e7ca042dbf4cc1c7f4e12cd842c7789f133'/>
<id>ed764e7ca042dbf4cc1c7f4e12cd842c7789f133</id>
<content type='text'>
This patch reverts one hunk of 677bd810eedce61edf15452491781ff046b92edc
"ACPI video: remove output switching control", namely the removal of
probing for _DOS/_DOD when searching for video devices.

This is needed on some Fujitsu Laptops (at least S7110, P8010) for the
ACPI backlight interface to work, as an these machines, neither ROM nor
posting methods are available, and after removal of output switching,
none of the caps triggers, which prevents the backlight search from
being entered.

Tested on a Fujitsu Lifebook S7110 and Fujitsu Lifebook P8010.
This probably fixes https://bugzilla.kernel.org/show_bug.cgi?id=27312
for the people who have no entry in /sys/class/backlight.

This is the complete list of public (starting with "_") methods implemented
on the S7110, BIOS rev 1.34:

\_SB_.PCI0.GFX0._ADR
\_SB_.PCI0.GFX0._DOS
\_SB_.PCI0.GFX0._DOD
\_SB_.PCI0.GFX0.CRT._ADR
\_SB_.PCI0.GFX0.CRT._DCS
\_SB_.PCI0.GFX0.CRT._DGS
\_SB_.PCI0.GFX0.CRT._DSS
\_SB_.PCI0.GFX0.LCD._ADR
\_SB_.PCI0.GFX0.LCD._BCL
\_SB_.PCI0.GFX0.LCD._BCM
\_SB_.PCI0.GFX0.LCD._BQC
\_SB_.PCI0.GFX0.LCD._DCS
\_SB_.PCI0.GFX0.LCD._DGS
\_SB_.PCI0.GFX0.LCD._DSS
\_SB_.PCI0.GFX0.LCD._PS0
\_SB_.PCI0.GFX0.LCD._PS3
\_SB_.PCI0.GFX0.TV._ADR
\_SB_.PCI0.GFX0.TV._DCS
\_SB_.PCI0.GFX0.TV._DGS
\_SB_.PCI0.GFX0.TV._DSS
\_SB_.PCI0.GFX0.DVI._ADR
\_SB_.PCI0.GFX0.DVI._DCS
\_SB_.PCI0.GFX0.DVI._DGS
\_SB_.PCI0.GFX0.DVI._DSS

Signed-off-by: Michael Karcher &lt;kernel@mkarcher.dialup.fu-berlin.de&gt;
Acked-by: Zhang Rui &lt;rui.zhang@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch reverts one hunk of 677bd810eedce61edf15452491781ff046b92edc
"ACPI video: remove output switching control", namely the removal of
probing for _DOS/_DOD when searching for video devices.

This is needed on some Fujitsu Laptops (at least S7110, P8010) for the
ACPI backlight interface to work, as an these machines, neither ROM nor
posting methods are available, and after removal of output switching,
none of the caps triggers, which prevents the backlight search from
being entered.

Tested on a Fujitsu Lifebook S7110 and Fujitsu Lifebook P8010.
This probably fixes https://bugzilla.kernel.org/show_bug.cgi?id=27312
for the people who have no entry in /sys/class/backlight.

This is the complete list of public (starting with "_") methods implemented
on the S7110, BIOS rev 1.34:

\_SB_.PCI0.GFX0._ADR
\_SB_.PCI0.GFX0._DOS
\_SB_.PCI0.GFX0._DOD
\_SB_.PCI0.GFX0.CRT._ADR
\_SB_.PCI0.GFX0.CRT._DCS
\_SB_.PCI0.GFX0.CRT._DGS
\_SB_.PCI0.GFX0.CRT._DSS
\_SB_.PCI0.GFX0.LCD._ADR
\_SB_.PCI0.GFX0.LCD._BCL
\_SB_.PCI0.GFX0.LCD._BCM
\_SB_.PCI0.GFX0.LCD._BQC
\_SB_.PCI0.GFX0.LCD._DCS
\_SB_.PCI0.GFX0.LCD._DGS
\_SB_.PCI0.GFX0.LCD._DSS
\_SB_.PCI0.GFX0.LCD._PS0
\_SB_.PCI0.GFX0.LCD._PS3
\_SB_.PCI0.GFX0.TV._ADR
\_SB_.PCI0.GFX0.TV._DCS
\_SB_.PCI0.GFX0.TV._DGS
\_SB_.PCI0.GFX0.TV._DSS
\_SB_.PCI0.GFX0.DVI._ADR
\_SB_.PCI0.GFX0.DVI._DCS
\_SB_.PCI0.GFX0.DVI._DGS
\_SB_.PCI0.GFX0.DVI._DSS

Signed-off-by: Michael Karcher &lt;kernel@mkarcher.dialup.fu-berlin.de&gt;
Acked-by: Zhang Rui &lt;rui.zhang@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / Wakeup: Enable button GPEs unconditionally during initialization</title>
<updated>2011-02-12T00:39:53+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2011-02-12T00:39:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2a5d24286e8bdafdc272b37ec5bdd9e977b3767c'/>
<id>2a5d24286e8bdafdc272b37ec5bdd9e977b3767c</id>
<content type='text'>
Commit 9630bdd (ACPI: Use GPE reference counting to support shared
GPEs) introduced a suspend regression where boxes resume immediately
after being suspended due to the lid or sleep button wakeup status
not being cleared properly.  This happens if the GPEs corresponding
to those devices are not enabled all the time, which apparently is
expected by some BIOSes.

To fix this problem, enable button and lid GPEs unconditionally
during initialization and keep them enabled all the time, regardless
of whether or not the ACPI button driver is used.

References: https://bugzilla.kernel.org/show_bug.cgi?id=27372
Reported-and-tested-by: Ferenc Wágner &lt;wferi@niif.hu&gt;
Cc: stable@kernel.org
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 9630bdd (ACPI: Use GPE reference counting to support shared
GPEs) introduced a suspend regression where boxes resume immediately
after being suspended due to the lid or sleep button wakeup status
not being cleared properly.  This happens if the GPEs corresponding
to those devices are not enabled all the time, which apparently is
expected by some BIOSes.

To fix this problem, enable button and lid GPEs unconditionally
during initialization and keep them enabled all the time, regardless
of whether or not the ACPI button driver is used.

References: https://bugzilla.kernel.org/show_bug.cgi?id=27372
Reported-and-tested-by: Ferenc Wágner &lt;wferi@niif.hu&gt;
Cc: stable@kernel.org
Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / ACPICA: Avoid crashing if _PRW is defined for the root object</title>
<updated>2011-02-12T00:39:15+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2011-02-12T00:39:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2d55951368faa32ff098398c56780ebb6405a3d9'/>
<id>2d55951368faa32ff098398c56780ebb6405a3d9</id>
<content type='text'>
Some ACPI BIOSes define _PRW for the root object which causes
acpi_setup_gpe_for_wake() to crash when trying to dereference the
bogus device_node pointer.  Avoid the crash by checking if
wake_device is not the root object before attempting to set up the
"implicit notify" mechanism for it.

The problem was introduced by commit bba63a296ffab20e08d9e8252d2f0d99
(ACPICA: Implicit notify support) that added the wake_device argument
to acpi_setup_gpe_for_wake().

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Some ACPI BIOSes define _PRW for the root object which causes
acpi_setup_gpe_for_wake() to crash when trying to dereference the
bogus device_node pointer.  Avoid the crash by checking if
wake_device is not the root object before attempting to set up the
"implicit notify" mechanism for it.

The problem was introduced by commit bba63a296ffab20e08d9e8252d2f0d99
(ACPICA: Implicit notify support) that added the wake_device argument
to acpi_setup_gpe_for_wake().

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: Fix acpi_os_read_memory() and acpi_os_write_memory() (v2)</title>
<updated>2011-02-08T22:37:16+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rjw@sisk.pl</email>
</author>
<published>2011-02-08T22:37:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=884b821fa27a5e3714d4871976d3e7c3abfa0d1b'/>
<id>884b821fa27a5e3714d4871976d3e7c3abfa0d1b</id>
<content type='text'>
The functions acpi_os_read_memory() and acpi_os_write_memory() do
two wrong things.  First, they shouldn't call rcu_read_unlock()
before the looked up address is actually used for I/O, because in
that case the iomap it belongs to may be removed before the I/O
is done.  Second, if they have to create a new mapping, they should
check the returned virtual address and tell the caller that the
operation failed if it is NULL (in fact, I think they even should not
attempt to map an address that's not present in one of the existing
ACPI iomaps, because that may cause problems to happen when they are
called from nonpreemptible context and their callers ought to know
what they are doing and map the requisite memory regions beforehand).

Make these functions call rcu_read_unlock() when the I/O is complete
(or if it's necessary to map the given address "on the fly") and
return an error code if the requested physical address is not present
in the existing ACPI iomaps and cannot be mapped.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
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<pre>
The functions acpi_os_read_memory() and acpi_os_write_memory() do
two wrong things.  First, they shouldn't call rcu_read_unlock()
before the looked up address is actually used for I/O, because in
that case the iomap it belongs to may be removed before the I/O
is done.  Second, if they have to create a new mapping, they should
check the returned virtual address and tell the caller that the
operation failed if it is NULL (in fact, I think they even should not
attempt to map an address that's not present in one of the existing
ACPI iomaps, because that may cause problems to happen when they are
called from nonpreemptible context and their callers ought to know
what they are doing and map the requisite memory regions beforehand).

Make these functions call rcu_read_unlock() when the I/O is complete
(or if it's necessary to map the given address "on the fly") and
return an error code if the requested physical address is not present
in the existing ACPI iomaps and cannot be mapped.

Signed-off-by: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
</pre>
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