<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/acpi, branch v3.2.47</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>ACPI / video: ignore BIOS initial backlight value for HP Pavilion g6</title>
<updated>2013-06-19T01:16:52+00:00</updated>
<author>
<name>Ash Willis</name>
<email>ashwillis.kernel@gmail.com</email>
</author>
<published>2013-05-29T01:27:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8de5f8abdee26b1dc13e98c401a68637df2ad0dc'/>
<id>8de5f8abdee26b1dc13e98c401a68637df2ad0dc</id>
<content type='text'>
commit 780a6ec640a3fed671fc2c40e4dd30c03eca3ac3 upstream.

This patch addresses kernel bug 56661. BIOS reports an incorrect
backlight value, causing the driver to switch off the backlight
completely during startup. This patch ignores the incorrect value from
BIOS.

References: https://bugzilla.kernel.org/show_bug.cgi?id=56661
Signed-off-by: Ash Willis &lt;ashwillis@programmer.net&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 780a6ec640a3fed671fc2c40e4dd30c03eca3ac3 upstream.

This patch addresses kernel bug 56661. BIOS reports an incorrect
backlight value, causing the driver to switch off the backlight
completely during startup. This patch ignores the incorrect value from
BIOS.

References: https://bugzilla.kernel.org/show_bug.cgi?id=56661
Signed-off-by: Ash Willis &lt;ashwillis@programmer.net&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: ignore BIOS initial backlight value for HP m4</title>
<updated>2013-06-19T01:16:52+00:00</updated>
<author>
<name>Alex Hung</name>
<email>alex.hung@canonical.com</email>
</author>
<published>2013-05-28T02:05:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=10254e3d0182b24685f1043183194c7a6d26a2e9'/>
<id>10254e3d0182b24685f1043183194c7a6d26a2e9</id>
<content type='text'>
commit fedbe9bc6fd3e14b1ffbb3dac407777ac4a3650c upstream.

On HP m4 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References: https://bugs.launchpad.net/bugs/1184501
Signed-off-by: Alex Hung &lt;alex.hung@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fedbe9bc6fd3e14b1ffbb3dac407777ac4a3650c upstream.

On HP m4 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References: https://bugs.launchpad.net/bugs/1184501
Signed-off-by: Alex Hung &lt;alex.hung@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI video: ignore BIOS initial backlight value for HP 1000</title>
<updated>2013-06-19T01:16:52+00:00</updated>
<author>
<name>Alex Hung</name>
<email>alex.hung@canonical.com</email>
</author>
<published>2013-05-06T08:23:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=36466ac6c36c955ec1e4eaf8f4ed6a192f430f9a'/>
<id>36466ac6c36c955ec1e4eaf8f4ed6a192f430f9a</id>
<content type='text'>
commit 4ef366c583d6180b1c951147869ee5a3038834f2 upstream.

On HP 1000 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References:: https://bugs.launchpad.net/bugs/1167760
Signed-off-by: Alex Hung &lt;alex.hung@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4ef366c583d6180b1c951147869ee5a3038834f2 upstream.

On HP 1000 lapops, BIOS reports minimum backlight on boot and
causes backlight to dim completely. This ignores the initial backlight
values and set to max brightness.

References:: https://bugs.launchpad.net/bugs/1167760
Signed-off-by: Alex Hung &lt;alex.hung@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI video: ignore BIOS backlight value for HP dm4</title>
<updated>2013-06-19T01:16:51+00:00</updated>
<author>
<name>Gustavo Maciel Dias Vieira</name>
<email>gustavo@sagui.org</email>
</author>
<published>2013-03-04T15:23:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c58c2d2597e052789db8fb0864355b3e504d286b'/>
<id>c58c2d2597e052789db8fb0864355b3e504d286b</id>
<content type='text'>
commit 771d09b3c4c45d4d534a83a68e6331b97fd82e15 upstream.

On a HP Pavilion dm4 laptop the BIOS sets minimum backlight on boot,
completely dimming the screen. Ignore this initial value for this
machine.

Signed-off-by: Gustavo Maciel Dias Vieira &lt;gustavo@sagui.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 771d09b3c4c45d4d534a83a68e6331b97fd82e15 upstream.

On a HP Pavilion dm4 laptop the BIOS sets minimum backlight on boot,
completely dimming the screen. Ignore this initial value for this
machine.

Signed-off-by: Gustavo Maciel Dias Vieira &lt;gustavo@sagui.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / video: Add "Asus UL30A" to ACPI video detect blacklist</title>
<updated>2013-05-30T13:35:05+00:00</updated>
<author>
<name>Bastian Triller</name>
<email>bastian.triller@gmail.com</email>
</author>
<published>2013-05-19T11:52:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2114b0ee38405ced73040bc1228c6cd42ecac8e2'/>
<id>2114b0ee38405ced73040bc1228c6cd42ecac8e2</id>
<content type='text'>
commit c8f6d8351ba8c89d5cd4c562552ec7ec29274e31 upstream.

Like on UL30VT, the ACPI video driver can't control backlight correctly on
Asus UL30A.  Vendor driver (asus-laptop) can work.  This patch is to
add "Asus UL30A" to ACPI video detect blacklist in order to use
asus-laptop for video control on the "Asus UL30A" rather than ACPI
video driver.

Signed-off-by: Bastian Triller &lt;bastian.triller@gmail.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c8f6d8351ba8c89d5cd4c562552ec7ec29274e31 upstream.

Like on UL30VT, the ACPI video driver can't control backlight correctly on
Asus UL30A.  Vendor driver (asus-laptop) can work.  This patch is to
add "Asus UL30A" to ACPI video detect blacklist in order to use
asus-laptop for video control on the "Asus UL30A" rather than ACPI
video driver.

Signed-off-by: Bastian Triller &lt;bastian.triller@gmail.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI / EC: Restart transaction even when the IBF flag set</title>
<updated>2013-05-30T13:34:56+00:00</updated>
<author>
<name>Lan Tianyu</name>
<email>tianyu.lan@intel.com</email>
</author>
<published>2013-05-06T03:23:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=694da87f929f867afe14efcc5683bc652dca4da8'/>
<id>694da87f929f867afe14efcc5683bc652dca4da8</id>
<content type='text'>
commit 28fe5c825f8e15744d04c7c1b8df197950923ecd upstream.

The EC driver works abnormally with IBF flag always set.
IBF means "The host has written a byte of data to the command
or data port, but the embedded controller has not yet read it".
If IBF is set in the EC status and not cleared, this will cause
all subsequent EC requests to fail with a timeout error.

Change the EC driver so that it doesn't refuse to restart a
transaction if IBF is set in the status.  Also increase the
number of transaction restarts to 5, as it turns out that 2
is not sufficient in some cases.

This bug happens on several different machines (Asus V1S,
Dell Latitude E6530, Samsung R719, Acer Aspire 5930G,
Sony Vaio SR19VN and others).

[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=14733
References: https://bugzilla.kernel.org/show_bug.cgi?id=15560
References: https://bugzilla.kernel.org/show_bug.cgi?id=15946
References: https://bugzilla.kernel.org/show_bug.cgi?id=42945
References: https://bugzilla.kernel.org/show_bug.cgi?id=48221
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 28fe5c825f8e15744d04c7c1b8df197950923ecd upstream.

The EC driver works abnormally with IBF flag always set.
IBF means "The host has written a byte of data to the command
or data port, but the embedded controller has not yet read it".
If IBF is set in the EC status and not cleared, this will cause
all subsequent EC requests to fail with a timeout error.

Change the EC driver so that it doesn't refuse to restart a
transaction if IBF is set in the status.  Also increase the
number of transaction restarts to 5, as it turns out that 2
is not sufficient in some cases.

This bug happens on several different machines (Asus V1S,
Dell Latitude E6530, Samsung R719, Acer Aspire 5930G,
Sony Vaio SR19VN and others).

[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=14733
References: https://bugzilla.kernel.org/show_bug.cgi?id=15560
References: https://bugzilla.kernel.org/show_bug.cgi?id=15946
References: https://bugzilla.kernel.org/show_bug.cgi?id=42945
References: https://bugzilla.kernel.org/show_bug.cgi?id=48221
Signed-off-by: Lan Tianyu &lt;tianyu.lan@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPICA: Fix possible buffer overflow during a field unit read operation</title>
<updated>2013-05-30T13:34:53+00:00</updated>
<author>
<name>Bob Moore</name>
<email>robert.moore@intel.com</email>
</author>
<published>2013-05-08T04:01:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=43d5219bffe5fe4b4e8c37959d4a9b37856af59f'/>
<id>43d5219bffe5fe4b4e8c37959d4a9b37856af59f</id>
<content type='text'>
commit 61388f9e5d93053cf399a356414f31f9b4814c6d upstream.

Can only happen under these conditions: 1) The DSDT version is 1,
meaning integers are 32-bits.  2) The field is between 33 and 64
bits long.

It applies cleanly back to ACPICA 20100806+ (Linux v2.6.37+).

Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Signed-off-by: Lv Zheng &lt;lv.zheng@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 61388f9e5d93053cf399a356414f31f9b4814c6d upstream.

Can only happen under these conditions: 1) The DSDT version is 1,
meaning integers are 32-bits.  2) The field is between 33 and 64
bits long.

It applies cleanly back to ACPICA 20100806+ (Linux v2.6.37+).

Signed-off-by: Bob Moore &lt;robert.moore@intel.com&gt;
Signed-off-by: Lv Zheng &lt;lv.zheng@intel.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI / ACPI: Don't query OSC support with all possible controls</title>
<updated>2013-05-13T14:02:12+00:00</updated>
<author>
<name>Yinghai Lu</name>
<email>yinghai@kernel.org</email>
</author>
<published>2013-03-28T04:28:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c08f24e209c8d0dbd2274af9327195d9ec1c2a53'/>
<id>c08f24e209c8d0dbd2274af9327195d9ec1c2a53</id>
<content type='text'>
commit 545d6e189a41c94c11f55045a771118eccc9d9eb upstream.

Found problem on system that firmware that could handle pci aer.
Firmware get error reporting after pci injecting error, before os boots.
But after os boots, firmware can not get report anymore, even pci=noaer
is passed.

Root cause: BIOS _OSC has problem with query bit checking.
It turns out that BIOS vendor is copying example code from ACPI Spec.
In ACPI Spec 5.0, page 290:

	If (Not(And(CDW1,1))) // Query flag clear?
	{	// Disable GPEs for features granted native control.
		If (And(CTRL,0x01)) // Hot plug control granted?
		{
			Store(0,HPCE) // clear the hot plug SCI enable bit
			Store(1,HPCS) // clear the hot plug SCI status bit
		}
	...
	}

When Query flag is set, And(CDW1,1) will be 1, Not(1) will return 0xfffffffe.
So it will get into code path that should be for control set only.
BIOS acpi code should be changed to "If (LEqual(And(CDW1,1), 0)))"

Current kernel code is using _OSC query to notify firmware about support
from OS and then use _OSC to set control bits.
During query support, current code is using all possible controls.
So will execute code that should be only for control set stage.

That will have problem when pci=noaer or aer firmware_first is used.
As firmware have that control set for os aer already in query support stage,
but later will not os aer handling.

We should avoid passing all possible controls, just use osc_control_set
instead.
That should workaround BIOS bugs with affected systems on the field
as more bios vendors are copying sample code from ACPI spec.

Signed-off-by: Yinghai Lu &lt;yinghai@kernel.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 545d6e189a41c94c11f55045a771118eccc9d9eb upstream.

Found problem on system that firmware that could handle pci aer.
Firmware get error reporting after pci injecting error, before os boots.
But after os boots, firmware can not get report anymore, even pci=noaer
is passed.

Root cause: BIOS _OSC has problem with query bit checking.
It turns out that BIOS vendor is copying example code from ACPI Spec.
In ACPI Spec 5.0, page 290:

	If (Not(And(CDW1,1))) // Query flag clear?
	{	// Disable GPEs for features granted native control.
		If (And(CTRL,0x01)) // Hot plug control granted?
		{
			Store(0,HPCE) // clear the hot plug SCI enable bit
			Store(1,HPCS) // clear the hot plug SCI status bit
		}
	...
	}

When Query flag is set, And(CDW1,1) will be 1, Not(1) will return 0xfffffffe.
So it will get into code path that should be for control set only.
BIOS acpi code should be changed to "If (LEqual(And(CDW1,1), 0)))"

Current kernel code is using _OSC query to notify firmware about support
from OS and then use _OSC to set control bits.
During query support, current code is using all possible controls.
So will execute code that should be only for control set stage.

That will have problem when pci=noaer or aer firmware_first is used.
As firmware have that control set for os aer already in query support stage,
but later will not os aer handling.

We should avoid passing all possible controls, just use osc_control_set
instead.
That should workaround BIOS bugs with affected systems on the field
as more bios vendors are copying sample code from ACPI spec.

Signed-off-by: Yinghai Lu &lt;yinghai@kernel.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: Add DMI entry for Sony VGN-FW41E_H</title>
<updated>2013-03-06T03:23:50+00:00</updated>
<author>
<name>Joseph Salisbury</name>
<email>joseph.salisbury@canonical.com</email>
</author>
<published>2013-02-05T00:16:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6684f6e7ac5669cfcaad4d89b09773b7139e30fb'/>
<id>6684f6e7ac5669cfcaad4d89b09773b7139e30fb</id>
<content type='text'>
commit 66f2fda93b67fa744d406e6dcf443f67bac204b6 upstream.

This patch adds a quirk to allow the Sony VGN-FW41E_H to suspend/resume
properly.

References: http://bugs.launchpad.net/bugs/1113547
Signed-off-by: Joseph Salisbury &lt;joseph.salisbury@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 66f2fda93b67fa744d406e6dcf443f67bac204b6 upstream.

This patch adds a quirk to allow the Sony VGN-FW41E_H to suspend/resume
properly.

References: http://bugs.launchpad.net/bugs/1113547
Signed-off-by: Joseph Salisbury &lt;joseph.salisbury@canonical.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>efi: Make 'efi_enabled' a function to query EFI facilities</title>
<updated>2013-02-06T04:33:50+00:00</updated>
<author>
<name>Matt Fleming</name>
<email>matt.fleming@intel.com</email>
</author>
<published>2012-11-14T09:42:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=06c73e442edec7cda81193276c72fda1abb96fb0'/>
<id>06c73e442edec7cda81193276c72fda1abb96fb0</id>
<content type='text'>
commit 83e68189745ad931c2afd45d8ee3303929233e7f upstream.

Originally 'efi_enabled' indicated whether a kernel was booted from
EFI firmware. Over time its semantics have changed, and it now
indicates whether or not we are booted on an EFI machine with
bit-native firmware, e.g. 64-bit kernel with 64-bit firmware.

The immediate motivation for this patch is the bug report at,

    https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557

which details how running a platform driver on an EFI machine that is
designed to run under BIOS can cause the machine to become
bricked. Also, the following report,

    https://bugzilla.kernel.org/show_bug.cgi?id=47121

details how running said driver can also cause Machine Check
Exceptions. Drivers need a new means of detecting whether they're
running on an EFI machine, as sadly the expression,

    if (!efi_enabled)

hasn't been a sufficient condition for quite some time.

Users actually want to query 'efi_enabled' for different reasons -
what they really want access to is the list of available EFI
facilities.

For instance, the x86 reboot code needs to know whether it can invoke
the ResetSystem() function provided by the EFI runtime services, while
the ACPI OSL code wants to know whether the EFI config tables were
mapped successfully. There are also checks in some of the platform
driver code to simply see if they're running on an EFI machine (which
would make it a bad idea to do BIOS-y things).

This patch is a prereq for the samsung-laptop fix patch.

Cc: David Airlie &lt;airlied@linux.ie&gt;
Cc: Corentin Chary &lt;corentincj@iksaif.net&gt;
Cc: Matthew Garrett &lt;mjg59@srcf.ucam.org&gt;
Cc: Dave Jiang &lt;dave.jiang@intel.com&gt;
Cc: Olof Johansson &lt;olof@lixom.net&gt;
Cc: Peter Jones &lt;pjones@redhat.com&gt;
Cc: Colin Ian King &lt;colin.king@canonical.com&gt;
Cc: Steve Langasek &lt;steve.langasek@canonical.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Konrad Rzeszutek Wilk &lt;konrad@kernel.org&gt;
Cc: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Matt Fleming &lt;matt.fleming@intel.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
[bwh: Backported to 3.2:
 - Adjust context (a lot)
 - Add efi_is_native() function from commit 5189c2a7c776
   ('x86: efi: Turn off efi_enabled after setup on mixed fw/kernel')
 - Make efi_init() bail out when booted non-native, as it would previously
   not be called in this case
 - Drop inapplicable changes to start_kernel()]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
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commit 83e68189745ad931c2afd45d8ee3303929233e7f upstream.

Originally 'efi_enabled' indicated whether a kernel was booted from
EFI firmware. Over time its semantics have changed, and it now
indicates whether or not we are booted on an EFI machine with
bit-native firmware, e.g. 64-bit kernel with 64-bit firmware.

The immediate motivation for this patch is the bug report at,

    https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557

which details how running a platform driver on an EFI machine that is
designed to run under BIOS can cause the machine to become
bricked. Also, the following report,

    https://bugzilla.kernel.org/show_bug.cgi?id=47121

details how running said driver can also cause Machine Check
Exceptions. Drivers need a new means of detecting whether they're
running on an EFI machine, as sadly the expression,

    if (!efi_enabled)

hasn't been a sufficient condition for quite some time.

Users actually want to query 'efi_enabled' for different reasons -
what they really want access to is the list of available EFI
facilities.

For instance, the x86 reboot code needs to know whether it can invoke
the ResetSystem() function provided by the EFI runtime services, while
the ACPI OSL code wants to know whether the EFI config tables were
mapped successfully. There are also checks in some of the platform
driver code to simply see if they're running on an EFI machine (which
would make it a bad idea to do BIOS-y things).

This patch is a prereq for the samsung-laptop fix patch.

Cc: David Airlie &lt;airlied@linux.ie&gt;
Cc: Corentin Chary &lt;corentincj@iksaif.net&gt;
Cc: Matthew Garrett &lt;mjg59@srcf.ucam.org&gt;
Cc: Dave Jiang &lt;dave.jiang@intel.com&gt;
Cc: Olof Johansson &lt;olof@lixom.net&gt;
Cc: Peter Jones &lt;pjones@redhat.com&gt;
Cc: Colin Ian King &lt;colin.king@canonical.com&gt;
Cc: Steve Langasek &lt;steve.langasek@canonical.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Konrad Rzeszutek Wilk &lt;konrad@kernel.org&gt;
Cc: Rafael J. Wysocki &lt;rjw@sisk.pl&gt;
Signed-off-by: Matt Fleming &lt;matt.fleming@intel.com&gt;
Signed-off-by: H. Peter Anvin &lt;hpa@linux.intel.com&gt;
[bwh: Backported to 3.2:
 - Adjust context (a lot)
 - Add efi_is_native() function from commit 5189c2a7c776
   ('x86: efi: Turn off efi_enabled after setup on mixed fw/kernel')
 - Make efi_init() bail out when booted non-native, as it would previously
   not be called in this case
 - Drop inapplicable changes to start_kernel()]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
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