linux-imx

ACPI: PM: Set enable_for_wake for wakeup GPEs during suspend-to-idle

I noticed that recently multiple systems (chromebooks) couldn't wake
from S0ix using LID or Keyboard after updating to a newer kernel. I
bisected and it turned up commit f941d3e41da7 ("ACPI: EC / PM: Disable
non-wakeup GPEs for suspend-to-idle"). I checked that the issue got
fixed if that commit was reverted.

I debugged and found that although PNP0C0D:00 (representing the LID)
is wake capable and should wakeup the system per the code in
acpi_wakeup_gpe_init() and in drivers/acpi/button.c:

localhost /sys # cat /proc/acpi/wakeup
Device  S-state   Status   Sysfs node
LID0      S4    *enabled   platform:PNP0C0D:00
CREC      S5    *disabled  platform:GOOG0004:00
                *disabled  platform:cros-ec-dev.1.auto
                *disabled  platform:cros-ec-accel.0
                *disabled  platform:cros-ec-accel.1
                *disabled  platform:cros-ec-gyro.0
                *disabled  platform:cros-ec-ring.0
                *disabled  platform:cros-usbpd-charger.2.auto
                *disabled  platform:cros-usbpd-logger.3.auto
D015      S3    *enabled   i2c:i2c-ELAN0000:00
PENH      S3    *enabled   platform:PRP0001:00
XHCI      S3    *enabled   pci:0000:00:14.0
GLAN      S4    *disabled
WIFI      S3    *disabled  pci:0000:00:14.3
localhost /sys #

On debugging, I found that its corresponding GPE is not being enabled.
The particular GPE's "gpe_register_info->enable_for_wake" does not
have any bits set when acpi_enable_all_wakeup_gpes() comes around to
use it. I looked at code and could not find any other code path that
should set the bits in "enable_for_wake" bitmask for the wake enabled
devices for s2idle.  [I do see that it happens for S3 in
acpi_sleep_prepare()].

Thus I used the same call to enable the GPEs for wake enabled devices,
and verified that this fixes the regression I was seeing on multiple
of my devices.

[ rjw: The problem is that commit f941d3e41da7 ("ACPI: EC / PM:
  Disable non-wakeup GPEs for suspend-to-idle") forgot to add
  the acpi_enable_wakeup_devices() call for s2idle along with
  acpi_enable_all_wakeup_gpes(). ]

Fixes: f941d3e41da7 ("ACPI: EC / PM: Disable non-wakeup GPEs for suspend-to-idle")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=203579
Signed-off-by: Rajat Jain <rajatja@google.com>
[ rjw: Subject & changelog ]
Cc: 5.0+ <stable@vger.kernel.org> # 5.0+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>