linux-kernel - [PATCH v1 7/9] platform/x86: asus-wmi: ROG Ally increase wait time, allow MCU powersave

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Date: Tue,  2 Apr 2024 14:34:51 +1300
From: "Luke D. Jones" <luke@...nes.dev>
To: hdegoede@...hat.com
Cc: corentin.chary@...il.com,
	ilpo.jarvinen@...ux.intel.com,
	platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Luke D. Jones" <luke@...nes.dev>
Subject: [PATCH v1 7/9] platform/x86: asus-wmi: ROG Ally increase wait time, allow MCU powersave

The previous work to allow the MCU to be resumed correctly after sleep
and resume tried to take the shortest possible time. However as work
continues in various other parts of the s2idle subsystems it has shown
that it wasn't entirely reliable.

If the MCU disable/enable call is done correctly the MCU fully removes
its USB endpoints, and this shows as a full USB device reconnection on
resume. When we tried to short this as much as possible sometimes the
MCU doesn't get to complete what it needs to do before going to low-power
and this affected the reconnection.

Through trial it is found that the minimum time required is approx 1200ms
to allow a proper disconnect and disable, and the same amount of time on
resume is required to prevent a rapid disconnect/reconnect happening on
seemingly random occasions. To be safe the time is now 1500ms for msleep.

Signed-off-by: Luke D. Jones <luke@...nes.dev>
---
 drivers/platform/x86/asus-wmi.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 2ff78e194801..ec249eca0d94 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -129,7 +129,7 @@ module_param(fnlock_default, bool, 0444);
 /* Controls the power state of the USB0 hub on ROG Ally which input is on */
 #define ASUS_USB0_PWR_EC0_CSEE "\\_SB.PCI0.SBRG.EC0.CSEE"
 /* 300ms so far seems to produce a reliable result on AC and battery */
-#define ASUS_USB0_PWR_EC0_CSEE_WAIT 300
+#define ASUS_USB0_PWR_EC0_CSEE_WAIT 1500
 
 static const char * const ashs_ids[] = { "ATK4001", "ATK4002", NULL };
 
@@ -4814,6 +4814,7 @@ static int asus_hotk_resume_early(struct device *device)
 	struct asus_wmi *asus = dev_get_drvdata(device);
 
 	if (asus->ally_mcu_usb_switch) {
+		/* sleep required to prevent USB0 being yanked then reappearing rapidly */
 		if (ACPI_FAILURE(acpi_execute_simple_method(NULL, ASUS_USB0_PWR_EC0_CSEE, 0xB8)))
 			dev_err(device, "ROG Ally MCU failed to connect USB dev\n");
 		else
@@ -4825,17 +4826,8 @@ static int asus_hotk_resume_early(struct device *device)
 static int asus_hotk_prepare(struct device *device)
 {
 	struct asus_wmi *asus = dev_get_drvdata(device);
-	int result, err;
 
 	if (asus->ally_mcu_usb_switch) {
-		/* When powersave is enabled it causes many issues with resume of USB hub */
-		result = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_MCU_POWERSAVE);
-		if (result == 1) {
-			dev_warn(device, "MCU powersave enabled, disabling to prevent resume issues");
-			err = asus_wmi_set_devstate(ASUS_WMI_DEVID_MCU_POWERSAVE, 0, &result);
-			if (err || result != 1)
-				dev_err(device, "Failed to set MCU powersave mode: %d\n", err);
-		}
 		/* sleep required to ensure USB0 is disabled before sleep continues */
 		if (ACPI_FAILURE(acpi_execute_simple_method(NULL, ASUS_USB0_PWR_EC0_CSEE, 0xB7)))
 			dev_err(device, "ROG Ally MCU failed to disconnect USB dev\n");
-- 
2.44.0