[PATCH v1 2/4] acpi/x86: s2idle: handle screen off/on calls outside of suspend sequence

[Antheas Kapenekakis <lkml@antheas.dev>]

Currently, the screen off/on calls are handled within the suspend
sequence, which is a deviation from Windows. This causes issues with
certain devices, such as the ROG Ally, which expects this call to be
executed with the kernel fully awake. The subsequent half-suspended
state makes the controller of the device to fail to suspend properly.

This patch calls the screen off/on callbacks before entering the suspend
sequence, which fixes this issue. In addition, it opens the possibility
of modelling a state such as "Screen Off" that mirrors Windows, as the
callbacks will be accessible and validated to work outside of the
suspend sequence.

Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
---
 kernel/power/suspend.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 19734b297527..afa95271ef00 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -507,6 +507,19 @@ int suspend_devices_and_enter(suspend_state_t state)
 
 	pm_suspend_target_state = state;
 
+	/*
+	 * Linux does not have the concept of a "Screen Off" state, so call
+	 * the platform functions for screen off prior to beginning the suspend
+	 * sequence, mirroring Windows which calls them outside of it as well.
+	 *
+	 * If Linux ever gains a "Screen Off" state, the following callbacks can
+	 * be replaced with a call that checks if we are in "Screen Off", in which
+	 * case they will NOOP and if not call them as a fallback.
+	 */
+	error = platform_suspend_screen_off();
+	if (error)
+		goto Screen_on;
+
 	if (state == PM_SUSPEND_TO_IDLE)
 		pm_set_suspend_no_platform();
 
@@ -540,6 +553,9 @@ int suspend_devices_and_enter(suspend_state_t state)
  Close:
 	platform_resume_end(state);
 	pm_suspend_target_state = PM_SUSPEND_ON;
+
+ Screen_on:
+	platform_suspend_screen_on();
 	return error;
 
  Recover_platform:
-- 
2.46.1