[PATCH v2 3/5] acpi/x86: s2idle: add quirk table for modern standby delays

Antheas Kapenekakis
2024-09-22T17:24:31Z

Unfortunately, some modern standby systems, including the ROG Ally, rely
on a delay between modern standby transitions. Add a quirk table for
introducing delays between modern standby transitions, and quirk the
ROG Ally on "Display Off", which needs a bit of time to turn off its
controllers prior to suspending (i.e., entering DRIPS).

Reported-by: Denis Benato <benato.denis96@gmail.com>
Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
---
include/linux/suspend.h | 5 +++++
kernel/power/suspend.c | 41 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+)

diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 8f33249cc067..d7e2a4d8ab0c 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -144,6 +144,11 @@ struct platform_s2idle_ops {
int (*display_on)(void);
};

+struct platform_s2idle_quirks {
+ int delay_display_off;
+ int delay_display_on;
+};
+
#ifdef CONFIG_SUSPEND
extern suspend_state_t pm_suspend_target_state;
extern suspend_state_t mem_sleep_current;
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 610f8ecaeebd..af2abdd2f8c3 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -11,6 +11,7 @@

#include <linux/string.h>
#include <linux/delay.h>
+#include <linux/dmi.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/console.h>
@@ -61,6 +62,30 @@ static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
enum s2idle_states __read_mostly s2idle_state;
static DEFINE_RAW_SPINLOCK(s2idle_lock);

+// The ROG Ally series disconnects its controllers on Display Off, without
+// holding a lock, introducing a race condition. Add a delay to allow the
+// controller to disconnect cleanly prior to suspend.
+static const struct platform_s2idle_quirks rog_ally_quirks = {
+ .delay_display_off = 500,
+};
+
+static const struct dmi_system_id platform_s2idle_quirks[] = {
+ {
+ .matches = {
+ DMI_MATCH(DMI_BOARD_NAME, "RC71L"),
+ },
+ .driver_data = (void *)&rog_ally_quirks
+ },
+ {
+ .matches = {
+ DMI_MATCH(DMI_BOARD_NAME, "RC72L"),
+ },
+ .driver_data = (void *)&rog_ally_quirks
+ },
+ {}
+};
+
+
/**
* pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
*
@@ -589,12 +614,26 @@ static int enter_state(suspend_state_t state)
if (state == PM_SUSPEND_TO_IDLE)
s2idle_begin();

+ /*
+ * Windows transitions between Modern Standby states slowly, over multiple
+ * seconds. Certain manufacturers may rely on this, introducing race
+ * conditions. Until Linux can support modern standby, add the relevant
+ * delays between transitions here.
+ */
+ const struct dmi_system_id *s2idle_sysid = dmi_first_match(
+ platform_s2idle_quirks
+ );
+ const struct platform_s2idle_quirks *s2idle_quirks = s2idle_sysid ?
+ s2idle_sysid->driver_data : NULL;
+
/*
* Linux does not have the concept of a "Screen Off" state, so call
* the platform functions for Display On/Off prior to the suspend
* sequence, mirroring Windows which calls them outside of it as well.
*/
platform_suspend_display_off();
+ if (s2idle_quirks && s2idle_quirks->delay_display_off)
+ msleep(s2idle_quirks->delay_display_off);

if (sync_on_suspend_enabled) {
trace_suspend_resume(TPS("sync_filesystems"), 0, true);
@@ -624,6 +663,8 @@ static int enter_state(suspend_state_t state)
Unlock:
mutex_unlock(&system_transition_mutex);

+ if (s2idle_quirks && s2idle_quirks->delay_display_on)
+ msleep(s2idle_quirks->delay_display_on);
platform_suspend_display_on();
return error;
}
--
2.46.1