[PATCH] ACPI: battery: Re-read battery information in the complete callback

[Ali Ahmet Memiş]

Since commit d33e89d12295 ("thermal: core: Suspend thermal zones later
and resume them earlier"), thermal zones are resumed from dpm_complete(),
before the PM_POST_SUSPEND notifier that re-reads _BIX and _BST. On
ThinkPad P1 Gen2 and P53, INT3403 _TMP calls \GTST which switches the EC
page selector (HIID) without taking the BATM mutex used by the battery
methods. ACPICA releases the interpreter lock around EC accesses so the
two methods interleave and _BIX often returns temperature page data
after resume.

Evaluate _BIX and _BST in the complete callback, which runs before
dpm_complete() resumes thermal zones and leave only the sysfs
re-registration to the notifier.

Fixes: d33e89d12295 ("thermal: core: Suspend thermal zones later and resume them earlier")
Reported-by: Charis Stratakis <c.stratakis@xxxxxxxxx>
Closes: https://lore.kernel.org/all/37N_jFulf7n-Z55NfKfE71C_wVPxYvZ0xD_iRUg2fXu7TypDiF5PStQ6siSfVBih6fThg5WoPes8U5ZQpfVm_teMFcUGXFxz2DdMbfSWuws=@proton.me/
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ali Ahmet Memiş <aliamemis@xxxxxxxxxxx>
---
Ran into this (report) while reading the EC firmware of my T490.
The P1 Gen2 EC has the same single page selector.

Tested on 7.3-rc7 with an SSDT that makes a thermal zone keep calling a
copy of the P1 Gen2 \GTST after resume.  _BIX was broken after 5 of 5
resumes without the patch and 0 of 5 with it.

Doing it in the resume callback also works but _BIX takes about 75 ms
there right after resume against about 35 ms here (and by the complete
callback all operation region providers have resumed too).

 drivers/acpi/battery.c | 62 ++++++++++++++++++++++++++++--------------
 1 file changed, 42 insertions(+), 20 deletions(-)

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
index 670853ec3a4d..34f2e78c4314 100644
--- a/drivers/acpi/battery.c
+++ b/drivers/acpi/battery.c
@@ -107,6 +107,7 @@ struct acpi_battery {
 	struct notifier_block pm_nb;
 	struct list_head list;
 	unsigned long flags;
+	bool resume_reregister;
 
 	struct mutex property_lock; /* Protects properties below. */
 	unsigned long update_time;
@@ -1209,29 +1210,15 @@ static int battery_notify(struct notifier_block *nb,
 	if (mode == PM_POST_SUSPEND || mode == PM_POST_HIBERNATION) {
 		guard(mutex)(&battery->update_lock);
 
-		if (!acpi_battery_present(battery))
+		if (!battery->resume_reregister)
 			return 0;
 
-		if (battery->bat) {
-			acpi_battery_refresh(battery);
-		} else {
-			int result;
-
-			scoped_guard(mutex, &battery->property_lock) {
-				result = acpi_battery_get_info(battery);
-				if (result)
-					return result;
-			}
+		battery->resume_reregister = false;
 
-			result = sysfs_add_battery(battery);
-			if (result)
-				return result;
-		}
+		if (battery->bat)
+			sysfs_remove_battery(battery);
 
-		scoped_guard(mutex, &battery->property_lock) {
-			acpi_battery_init_alarm(battery);
-			acpi_battery_get_state(battery);
-		}
+		return sysfs_add_battery(battery);
 	}
 
 	return 0;
@@ -1450,7 +1437,42 @@ static int acpi_battery_resume(struct device *dev)
 	return 0;
 }
 
-static DEFINE_SIMPLE_DEV_PM_OPS(acpi_battery_pm, NULL, acpi_battery_resume);
+static void acpi_battery_complete(struct device *dev)
+{
+	struct acpi_battery *battery = dev_get_drvdata(dev);
+
+	if (!battery)
+		return;
+
+	guard(mutex)(&battery->update_lock);
+
+	if (!acpi_battery_present(battery))
+		return;
+
+	/*
+	 * Evaluate _BIX and _BST here before thermal zones are resumed, as
+	 * some firmware shares the EC window with _TMP without locking.
+	 */
+	guard(mutex)(&battery->property_lock);
+
+	if (battery->bat) {
+		int power_unit = battery->power_unit;
+
+		acpi_battery_get_info(battery);
+		if (power_unit != battery->power_unit)
+			battery->resume_reregister = true;
+	} else if (!acpi_battery_get_info(battery)) {
+		battery->resume_reregister = true;
+	}
+
+	acpi_battery_init_alarm(battery);
+	acpi_battery_get_state(battery);
+}
+
+static const struct dev_pm_ops acpi_battery_pm = {
+	SYSTEM_SLEEP_PM_OPS(NULL, acpi_battery_resume)
+	.complete = pm_sleep_ptr(acpi_battery_complete),
+};
 
 static struct platform_driver acpi_battery_driver = {
 	.probe = acpi_battery_probe,
-- 
2.55.0