linux-toradex.git/drivers/acpi/ec.c, branch v4.9.41

Revert "ACPI / EC: Enable event freeze mode..." to fix a regression

2017-07-27T22:08:04+00:00

commit 9c40f956ce9b331493347d1b3cb7e384f7dc0581 upstream.

On Lenovo ThinkPad X1 Carbon - the 5th Generation, enabling an earlier
EC event freezing timing causes acpitz-virtual-0 to report a stuck
48C temparature.  And with EC firmware revisioned as 1.14, without
reverting back to old EC event freezing timing, the fan still blows
up after a system resume.

This reverts the culprit change so that the regression can be fixed
without upgrading the EC firmware.

Fixes: d30283057ecd (ACPI / EC: Enable event freeze mode to improve event handling)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=191181#c168
Tested-by: Damjan Georgievski 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

ACPI / EC: Drop EC noirq hooks to fix a regression

2017-07-27T22:08:04+00:00

commit 662591461c4b9a1e3b9b159dbf37648a585ebaae upstream.

According to bug reports, although the busy polling mode can make
noirq stages execute faster, it causes abnormal fan blowing up after
system resume (see the first link below for a video demonstration)
on Lenovo ThinkPad X1 Carbon - the 5th Generation.  The problem can
be fixed by upgrading the EC firmware on that machine.

However, many reporters confirm that the problem can be fixed by
stopping busy polling during suspend/resume and for some of them
upgrading the EC firmware is not an option.

For this reason, drop the noirq stage hooks from the EC driver
to fix the regression.

Fixes: c3a696b6e8f8 (ACPI / EC: Use busy polling mode when GPE is not enabled)
Link: https://youtu.be/9NQ9x-Jm99Q
Link: https://bugzilla.kernel.org/show_bug.cgi?id=196129
Reported-by: Andreas Lindhe 
Tested-by: Gjorgji Jankovski 
Tested-by: Damjan Georgievski 
Tested-by: Fernando Chaves 
Tested-by: Tomislav Ivek 
Tested-by: Denis P. 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

ACPI / EC: Use busy polling mode when GPE is not enabled

2017-04-21T07:31:24+00:00

commit c3a696b6e8f8f75f9f75e556a9f9f6472eae2655 upstream.

When GPE is not enabled, it is not efficient to use the wait polling mode
as it introduces an unexpected scheduler delay.
So before the GPE handler is installed, this patch uses busy polling mode
for all EC(s) and the logic can be applied to non boot EC(s) during the
suspend/resume process.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=191561
Tested-by: Jakobus Schurz 
Tested-by: Chen Yu 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

ACPI / EC: Fix unused function warning when CONFIG_PM_SLEEP=n

2016-10-10T00:22:20+00:00

Signed-off-by: Eric Biggers 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix issues related to boot_ec

2016-09-10T00:33:50+00:00

There are issues related to the boot_ec:
1. If acpi_ec_remove() is invoked, boot_ec will also be freed, this is not
   expected as the boot_ec could be enumerated via ECDT.
2. Address space handler installation/unstallation lead to unexpected _REG
   evaluations.
This patch adds acpi_is_boot_ec() check to be used to fix the above issues.
However, since acpi_ec_remove() actually won't be invoked, this patch
doesn't handle the reference counting of "struct acpi_ec", it only ensures
the correctness of the boot_ec destruction during the boot.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=153511
Reported-and-tested-by: Jonh Henderson 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a gap that ECDT EC cannot handle EC events

2016-09-10T00:33:50+00:00

It is possible to register _Qxx from namespace and use the ECDT EC to
perform event handling. The reported bug reveals that Windows is using ECDT
in this way in case the namespace EC is not present. This patch facilitates
Linux to support ECDT in this way.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=115021
Reported-and-tested-by: Luya Tshimbalanga 
Tested-by: Jonh Henderson 
Reviewed-by: Peter Wu 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a memory leakage issue in acpi_ec_add()

2016-09-10T00:33:49+00:00

When the handler installation failed, there was no code to free the
allocated EC device. This patch fixes this memory leakage issue.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=115021
Reported-and-tested-by: Luya Tshimbalanga 
Tested-by: Jonh Henderson 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Cleanup first_ec/boot_ec code

2016-09-10T00:33:49+00:00

In order to support full ECDT (driving the ECDT EC after probing the
namespace EC), we need to change our EC device alloc/free algorithm, ensure
not to free old boot EC before qualifying new boot EC.
This patch achieves this by cleaning up first_ec/boot_ec logic:
1. first_ec: used to perform transactions, so it is assigned in new
   acpi_ec_setup() function.
2. boot_ec: used to track early EC device, so it is assigned in new
   acpi_config_boot_ec() function which explictly tells the driver to save
   the EC device as early EC device.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=115021
Reported-and-tested-by: Luya Tshimbalanga 
Tested-by: Jonh Henderson 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Enable event freeze mode to improve event handling for suspend process

2016-08-30T22:32:11+00:00

This patch enables the event freeze mode, flushing the EC event handling in
.suspend() callback. This feature is experimental, if it is bisected out to
be the cause of the real issues, please report the issues to the kernel
bugzilla for further root causing and improvement.

This mode eliminates useless _Qxx handling during the power saving
operations, thus can help to tune the power saving operations faster. Tests
show that this mode can efficiently block flooding _Qxx during the suspend
process and tune the speed of the suspend faster.

Signed-off-by: Lv Zheng 
Tested-by: Todd E Brandt 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Add PM operations to improve event handling for suspend process

2016-08-30T22:32:11+00:00

In the original EC driver, though the event handling is not explicitly
stopped, the EC driver is actually not able to handle events during the
noirq stage as the EC driver is not prepared to handle the EC events in the
polling mode. So if there is no advance_transaction() triggered, the EC
driver couldn't notice the EC events.
However, do we actually need to handle EC events during suspend/resume
stage? EC events are mostly useless for the suspend/resume period (key
strokes and battery/thermal updates, etc.,), and the useful ones (lid
close, power/sleep button press) should have already been delivered to the
OSPM to trigger the power saving operations.
Thus this patch implements acpi_ec_disable_event() to be a reverse call of
acpi_ec_enable_event(), with which, the EC driver is able to stop handling
the EC events in a position before entering the noirq stage.

Since there are actually 2 choices for us:
1. implement event handling in polling mode;
2. stop event handling before entering noirq stage.
And this patch only implements the second choice using .suspend() callback.
Thus this is experimental (first choice is better? or different hook
position is better?). This patch finally keeps the old behavior by default
and prepares a boot parameter to enable this feature.

The differences of the event handling availability between the old behavior
(this patch is not applied) and the new behavior (this patch is applied)
are as follows:
                        !FreezeEvents   FreezeEvents
before suspend          Y               Y
suspend before EC       Y               Y
suspend after EC        Y               N
suspend_late            Y               N
suspend_noirq           Y (actually N)  N
resume_noirq            Y (actually N)  N
resume_late             Y (actually N)  N
resume before EC        Y (actually N)  N
resume after EC         Y               Y
after resume            Y               Y
Where "actually N" means if there is no EC transactions, the EC driver
is actually not able to notice the pending events.

We can see that FreezeEvents is the only approach now can actually flush
the EC event handling with both query commands and _Qxx evaluations
flushed, other modes can only flush the EC event handling with only query
commands flushed, _Qxx evaluations occurred after stopping the EC driver
may end up failure due to the failure of the EC transaction carried out in
the _Qxx control methods.

We also can see that this feature should be able to trigger some platform
notifications later than resuming other drivers.

Signed-off-by: Lv Zheng 
Tested-by: Todd E Brandt 
Signed-off-by: Rafael J. Wysocki