Per Windows Precision Touchpad guidelines:
> The latency mode feature report is sent by the host to a Windows
> Precision Touchpad to indicate when high latency is desirable for
> power savings and, conversely, when normal latency is desired for
> operation.
>
> For USB-connected Windows Precision Touchpads, this enables the device
> to disambiguate between being suspended for inactivity (runtime IDLE)
> and being suspended because the system is entering S3 or Connected
> Standby.
The current implementation would set the latency to normal on device initialization,
but we didn't set the device to high latency on suspend.
Signed-off-by: Blaž Hrastnik <blaz@xxxxxxx>
---
drivers/hid/hid-multitouch.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index d670bcd57..28bac0f39 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -1746,6 +1746,13 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
}
#ifdef CONFIG_PM
+static int mt_suspend(struct hid_device *hdev, pm_message_t state)
+{
+ /* High latency is desirable for power savings during S3/S0ix */
+ mt_set_modes(hdev, HID_LATENCY_HIGH, true, true);
+ return 0;
+}
+
static int mt_reset_resume(struct hid_device *hdev)
{
mt_release_contacts(hdev);
@@ -1761,6 +1768,8 @@ static int mt_resume(struct hid_device *hdev)
hid_hw_idle(hdev, 0, 0, HID_REQ_SET_IDLE);
+ mt_set_modes(hdev, HID_LATENCY_NORMAL, true, true);
+
return 0;
}
#endif
@@ -2150,6 +2159,7 @@ static struct hid_driver mt_driver = {
.event = mt_event,
.report = mt_report,
#ifdef CONFIG_PM
+ .suspend = mt_suspend,
.reset_resume = mt_reset_resume,
.resume = mt_resume,
#endif
--
2.29.2
