linux-toradex.git/drivers/acpi/button.c, branch v4.9.16 Linux kernel for Apalis and Colibri modules ACPI / button: Fix an issue in button.lid_init_state=ignore mode 2016-08-30T23:06:20+00:00 Lv Zheng lv.zheng@intel.com 2016-08-17T08:22:58+00:00 dfa46c50f65b6ca10cea389327a6f1f1749bc633 On most platforms, _LID returning value, lid open/close events are all reliable, but there are exceptions. Some AML tables report wrong initial lid state [1], and some of them never report lid open state [2]. The usage model on such buggy platforms is: 1. The initial lid state returned from _LID is not reliable; 2. The lid open event is not reliable; 3. The lid close event is always reliable, used by the platform firmware to trigger OSPM power saving operations. This usage model is not compliant to the Linux SW_LID model as the Linux userspace is very strict to the reliability of the open events. In order not to trigger issues on such buggy platforms, the ACPI button driver currently implements a lid_init_state=open quirk to send additional "open" event after resuming. However, this is still not sufficient because: 1. Some special usage models (e.x., the dark resume scenario) cannot be supported by this mode. 2. If a "close" event is not used to trigger "suspend", then the subsequent "close" events cannot be seen by the userspace. So we need to stop sending the additional "open" event and switch the driver to lid_init_state=ignore mode and make sure the platform triggered events can be reliably delivered to the userspace. The userspace programs then can be changed to not to be strict to the "open" events on such buggy platforms. Why will the subsequent "close" events be lost? This is because the input layer automatically filters redundant events for switch events. Thus given that the buggy AML tables do not guarantee paired "open"/"close" events, the ACPI button driver currently is not able to guarantee that the platform triggered reliable events can be always be seen by the userspace via SW_LID. This patch adds a mechanism to insert lid events as a compensation for the platform triggered ones to form a complete event switches in order to make sure that the platform triggered events can always be reliably delivered to the userspace. This essentially guarantees that the platform triggered reliable "close" events will always be relibly delivered to the userspace. However this mechanism is not suitable for lid_init_state=open/method as it should not send the complement switch event for the unreliable initial lid state notification. 2 unreliable events can trigger unexpected behavior. Thus this patch only implements this mechanism for lid_init_state=ignore. Known issues: 1. Possible alternative approach This approach is based on the fact that Linux requires a switch event type for LID events. Another approach is to use key event type to implement ACPI lid events. With SW event type, since ACPI button driver inserts wrong lid events, there could be a potential issue that an "open" event issued from some AML update methods could result in a wrong "close" event to be delivered to the userspace. While using KEY event type, there is no such problem. However there may not be such a kind of real case, and if there is such a case, it is worked around in this patch as the complement switch event is only generated for "close" event in order to deliver the reliable "close" event to the userspace. Link: https://bugzilla.kernel.org/show_bug.cgi?id=89211 # [1] Link: https://bugzilla.kernel.org/show_bug.cgi?id=106151 # [1] Link: https://bugzilla.kernel.org/show_bug.cgi?id=106941 # [2] Signed-off-by: Lv Zheng <lv.zheng@intel.com> Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
On most platforms, _LID returning value, lid open/close events are all
reliable, but there are exceptions. Some AML tables report wrong initial
lid state [1], and some of them never report lid open state [2].
The usage model on such buggy platforms is:
1. The initial lid state returned from _LID is not reliable;
2. The lid open event is not reliable;
3. The lid close event is always reliable, used by the platform firmware to
   trigger OSPM power saving operations.
This usage model is not compliant to the Linux SW_LID model as the Linux
userspace is very strict to the reliability of the open events.

In order not to trigger issues on such buggy platforms, the ACPI button
driver currently implements a lid_init_state=open quirk to send additional
"open" event after resuming. However, this is still not sufficient because:
1. Some special usage models (e.x., the dark resume scenario) cannot be
   supported by this mode.
2. If a "close" event is not used to trigger "suspend", then the subsequent
   "close" events cannot be seen by the userspace.
So we need to stop sending the additional "open" event and switch the
driver to lid_init_state=ignore mode and make sure the platform triggered
events can be reliably delivered to the userspace. The userspace programs
then can be changed to not to be strict to the "open" events on such buggy
platforms.

Why will the subsequent "close" events be lost? This is because the input
layer automatically filters redundant events for switch events. Thus given
that the buggy AML tables do not guarantee paired "open"/"close" events,
the ACPI button driver currently is not able to guarantee that the platform
triggered reliable events can be always be seen by the userspace via
SW_LID.

This patch adds a mechanism to insert lid events as a compensation for the
platform triggered ones to form a complete event switches in order to make
sure that the platform triggered events can always be reliably delivered
to the userspace. This essentially guarantees that the platform triggered
reliable "close" events will always be relibly delivered to the userspace.

However this mechanism is not suitable for lid_init_state=open/method as
it should not send the complement switch event for the unreliable initial
lid state notification. 2 unreliable events can trigger unexpected
behavior. Thus this patch only implements this mechanism for
lid_init_state=ignore.

Known issues:
1. Possible alternative approach
   This approach is based on the fact that Linux requires a switch event
   type for LID events. Another approach is to use key event type to
   implement ACPI lid events.
   With SW event type, since ACPI button driver inserts wrong lid events,
   there could be a potential issue that an "open" event issued from some
   AML update methods could result in a wrong "close" event to be delivered
   to the userspace. While using KEY event type, there is no such problem.
   However there may not be such a kind of real case, and if there is such
   a case, it is worked around in this patch as the complement switch event
   is only generated for "close" event in order to deliver the reliable
   "close" event to the userspace.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=89211 # [1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106151 # [1]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106941 # [2]
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / button: remove pointer to old lid_sysfs on unbind 2016-08-02T23:27:20+00:00 Benjamin Tissoires benjamin.tissoires@redhat.com 2016-07-29T15:08:41+00:00 e370cc8640305aa2fa42b852cccd89e80c28d9a0 When we removed the procfs dir on error or if the driver is unbound, the two variables acpi_lid_dir and acpi_button_dir were not reset. On the next rebind, those static variables were not null and we couldn't re-register the device again. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Acked-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
When we removed the procfs dir on error or if the driver is
unbound, the two variables acpi_lid_dir and acpi_button_dir
were not reset. On the next rebind, those static variables
were not null and we couldn't re-register the device again.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / button: Add quirks for initial lid state notification 2016-06-22T00:10:17+00:00 Lv Zheng lv.zheng@intel.com 2016-06-01T10:10:48+00:00 3540c32a9ae4cb23ab70f7798f45affc02762fa7 Linux userspace (systemd-logind) keeps on rechecking lid state when the lid state is closed. If it failed to update the lid state to open after boot/resume, the system suspending right after the boot/resume could be resulted. Graphics drivers also use the lid notifications to implment MODESET_ON_LID_OPEN option. Before the situation is improved from the userspace and from the graphics driver, users can simply configure ACPI button driver to send initial "open" lid state using button.lid_init_state=open to avoid such kind of issues. And our ultimate target should be making button.lid_init_state=ignore the default behavior. This patch implements the 2 options and keep the old behavior (button.lid_init_state=method). Link: https://lkml.org/2016/3/7/460 Link: https://github.com/systemd/systemd/issues/2087 Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Linux userspace (systemd-logind) keeps on rechecking lid state when the
lid state is closed. If it failed to update the lid state to open after
boot/resume, the system suspending right after the boot/resume could be
resulted.

Graphics drivers also use the lid notifications to implment
MODESET_ON_LID_OPEN option.

Before the situation is improved from the userspace and from the graphics
driver, users can simply configure ACPI button driver to send initial
"open" lid state using button.lid_init_state=open to avoid such kind of
issues.

And our ultimate target should be making button.lid_init_state=ignore
the default behavior.  This patch implements the 2 options and keep the
old behavior (button.lid_init_state=method).

Link: https://lkml.org/2016/3/7/460
Link: https://github.com/systemd/systemd/issues/2087
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / button: Refactor functions to eliminate redundant code 2016-06-22T00:10:15+00:00 Lv Zheng lv.zheng@intel.com 2016-06-01T10:10:42+00:00 ee7e22653f5077169ec706b5a140a3be9db381e7 (Correct a wrong macro usage.) This patch simplies the code by merging some redundant code. No functional changes. Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
(Correct a wrong macro usage.)

This patch simplies the code by merging some redundant code.

No functional changes.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / button: Remove initial lid state notification 2016-06-22T00:10:14+00:00 Lv Zheng lv.zheng@intel.com 2016-06-01T10:10:34+00:00 c2dd420034f24f356b86f90222ef19148b82a5c1 The _LID control method's initial returning value is not reliable. The _LID control method is described to return the "current" lid state. However the word of "current" has ambiguity, many BIOSen return the lid state upon the last lid notification instead of returning the lid state upon the last _LID evaluation. There won't be difference when the _LID control method is evaluated during the runtime, the problem is its initial returning value. When the BIOSen implement this control method with cached value, the initial returning value is likely not reliable. There are simply so many examples retuning "close" as initial lid state (Link 1), sending this state to the userspace causes suspending right after booting/resuming. Since the lid state is implemented by the BIOSen, the kernel lid driver has no idea how it can be correct, this patch stops sending the initial lid state to the userspace to try to avoid sending the wrong lid state to the userspace to trigger such kind of wrong suspending. This actually reverts the following commit introduced for fixing a Novell bug: Commit: 23de5d9ef2a4bbc4f733f58311bcb7cf6239c813 Subject: ACPI: button: send initial lid state after add and resume Link: https://bugzilla.kernel.org/show_bug.cgi?id=89211 Link: https://bugzilla.kernel.org/show_bug.cgi?id=106151 Link: https://bugzilla.kernel.org/show_bug.cgi?id=106941 Link: https://bugzilla.novell.com/show_bug.cgi?id=326814 Signed-off-by: Lv Zheng <lv.zheng@intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
The _LID control method's initial returning value is not reliable.

The _LID control method is described to return the "current" lid state.
However the word of "current" has ambiguity, many BIOSen return the lid
state upon the last lid notification instead of returning the lid state
upon the last _LID evaluation. There won't be difference when the _LID
control method is evaluated during the runtime, the problem is its initial
returning value. When the BIOSen implement this control method with cached
value, the initial returning value is likely not reliable. There are simply
so many examples retuning "close" as initial lid state (Link 1), sending
this state to the userspace causes suspending right after booting/resuming.

Since the lid state is implemented by the BIOSen, the kernel lid driver has
no idea how it can be correct, this patch stops sending the initial lid
state to the userspace to try to avoid sending the wrong lid state to the
userspace to trigger such kind of wrong suspending. This actually reverts
the following commit introduced for fixing a Novell bug:

  Commit: 23de5d9ef2a4bbc4f733f58311bcb7cf6239c813
  Subject: ACPI: button: send initial lid state after add and resume

Link: https://bugzilla.kernel.org/show_bug.cgi?id=89211
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106151
Link: https://bugzilla.kernel.org/show_bug.cgi?id=106941
Link: https://bugzilla.novell.com/show_bug.cgi?id=326814
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI: Remove FSF mailing addresses 2015-07-08T00:27:32+00:00 Jarkko Nikula jarkko.nikula@linux.intel.com 2015-06-26T08:27:41+00:00 4c62dbbce902cf2afa88cac89ec67c828160f431 There is no need to carry potentially outdated Free Software Foundation mailing address in file headers since the COPYING file includes it. Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
There is no need to carry potentially outdated Free Software Foundation
mailing address in file headers since the COPYING file includes it.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / button: Do not propagate wakeup-from-suspend events 2014-07-22T22:59:04+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2014-07-22T22:59:04+00:00 e71eeb2a6bcc6282b95215eb353a3ac9ce3e0de3 During system suspend mark ACPI buttons (other than the lid) as "suspended" and if in that state, report wakeup events on button events, but do not propagate those events up the stack. This prevents systems from being turned off after a button-triggered wakeup from the "freeze" sleep state. Link: https://bugzilla.kernel.org/show_bug.cgi?id=77611 Tested-on: Acer Aspire S5, Toshiba Portege R500 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
During system suspend mark ACPI buttons (other than the lid) as
"suspended" and if in that state, report wakeup events on button
events, but do not propagate those events up the stack.

This prevents systems from being turned off after a button-triggered
wakeup from the "freeze" sleep state.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=77611
Tested-on: Acer Aspire S5, Toshiba Portege R500
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / button: Add ACPI Button event via netlink routine 2014-03-19T01:06:15+00:00 Lan Tianyu tianyu.lan@intel.com 2014-03-15T17:37:13+00:00 0bf6368ee8f25826d0645c0f7a4f17c8845356a4 Commit 1696d9d (ACPI: Remove the old /proc/acpi/event interface) removed ACPI Button event which originally was sent to userspace via /proc/acpi/event. This caused ACPI shutdown regression on gentoo in VirtualBox. Now ACPI events are sent to userspace via netlink, so add ACPI Button event back via netlink routine. References: https://bugzilla.kernel.org/show_bug.cgi?id=71721 Reported-and-tested-by: Richard Musil <richard.musil@gmail.com> Signed-off-by: Lan Tianyu <tianyu.lan@intel.com> Cc: 3.11+ <stable@vger.kernel.org> # 3.11+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
Commit 1696d9d (ACPI: Remove the old /proc/acpi/event interface)
removed ACPI Button event which originally was sent to userspace via
/proc/acpi/event. This caused ACPI shutdown regression on gentoo
in VirtualBox. Now ACPI events are sent to userspace via netlink,
so add ACPI Button event back via netlink routine.

References: https://bugzilla.kernel.org/show_bug.cgi?id=71721
Reported-and-tested-by: Richard Musil <richard.musil@gmail.com>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Cc: 3.11+ <stable@vger.kernel.org> # 3.11+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPI / button: fix button driver compile error when CONFIG_PM_SLEEP is undefined 2014-02-13T14:13:44+00:00 Shuah Khan shuah.kh@samsung.com 2014-02-13T03:19:07+00:00 2de9fd17c0359fea0c2ab5ae393c40d6d299bcaf The ACPI button driver defines acpi_button_resume() when CONFIG_PM_SLEEP is defined. This results in the following compile error when CONFIG_PM_SLEEP is undefined: drivers/acpi/button.c:85:8: error: ‘acpi_button_resume’ undeclared here (not in a function) Signed-off-by: Shuah Khan <shuah.kh@samsung.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> 
The ACPI button driver defines acpi_button_resume() when
CONFIG_PM_SLEEP is defined. This results in the following
compile error when CONFIG_PM_SLEEP is undefined:

drivers/acpi/button.c:85:8: error: ‘acpi_button_resume’ undeclared here (not in a function)

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branches 'acpi-gpe', 'acpi-video', 'acpi-thermal', 'acpi-processor', 'acpi-sleep' 2014-01-12T22:46:55+00:00 Rafael J. Wysocki rafael.j.wysocki@intel.com 2014-01-12T22:46:55+00:00 bcc7201a91176f815f48f8ad889a20c5c829d9a9 * acpi-gpe: ACPI / EC: disable GPE before removing GPE handler ACPI / Button: Fix enabling button GPEs twice * acpi-video: ACPI: Blacklist Win8 OSI for some HP laptop 2013 models ACPI / video: Fix typo in video_detect.c * acpi-thermal: ACPI / thermal: remove const from thermal_zone_device_ops declaration * acpi-processor: ACPI / scan: bail out early if failed to parse APIC ID for CPU * acpi-sleep: ACPI / sleep: remove panic in case hardware has changed after S4 
* acpi-gpe:
  ACPI / EC: disable GPE before removing GPE handler
  ACPI / Button: Fix enabling button GPEs twice

* acpi-video:
  ACPI: Blacklist Win8 OSI for some HP laptop 2013 models
  ACPI / video: Fix typo in video_detect.c

* acpi-thermal:
  ACPI / thermal: remove const from thermal_zone_device_ops declaration

* acpi-processor:
  ACPI / scan: bail out early if failed to parse APIC ID for CPU

* acpi-sleep:
  ACPI / sleep: remove panic in case hardware has changed after S4