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* HID: multitouch: Set to high latency mode on suspend.
@ 2020-12-19  4:47 Blaž Hrastnik
  2021-01-14 16:55 ` Benjamin Tissoires
  2021-01-26 10:09 ` Jiri Kosina
  0 siblings, 2 replies; 4+ messages in thread
From: Blaž Hrastnik @ 2020-12-19  4:47 UTC (permalink / raw)
  To: Jiri Kosina, Benjamin Tissoires, linux-input

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@mxxn.io>
---
 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


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-01-26 10:12 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-19  4:47 HID: multitouch: Set to high latency mode on suspend Blaž Hrastnik
2021-01-14 16:55 ` Benjamin Tissoires
2021-01-15  4:27   ` Blaž Hrastnik
2021-01-26 10:09 ` Jiri Kosina

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