linux-input.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
To: "Blaž Hrastnik" <blaz@mxxn.io>
Cc: Jiri Kosina <jikos@kernel.org>,
	"open list:HID CORE LAYER" <linux-input@vger.kernel.org>
Subject: Re: HID: multitouch: Set to high latency mode on suspend.
Date: Thu, 14 Jan 2021 17:55:30 +0100	[thread overview]
Message-ID: <CAO-hwJ+iA2vMMVEukDFGg_L6RPSRVfEhnB71yaTf-yPgkxLLNg@mail.gmail.com> (raw)
In-Reply-To: <2b4c5881-2047-407f-8bb4-623d9bd167c7@www.fastmail.com>

Hi Blaž,

On Sat, Dec 19, 2020 at 5:55 AM Blaž Hrastnik <blaz@mxxn.io> wrote:
>
> 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.

Just a couple of quick questions, do you have any reason to implement
this besides just trying to match the specification?

Have you checked if Windows is doing the same thing?

Cheers,
Benjamin



>
> 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
>


  reply	other threads:[~2021-01-14 16:57 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-19  4:47 Blaž Hrastnik
2021-01-14 16:55 ` Benjamin Tissoires [this message]
2021-01-15  4:27   ` Blaž Hrastnik
2021-01-26 10:09 ` Jiri Kosina

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAO-hwJ+iA2vMMVEukDFGg_L6RPSRVfEhnB71yaTf-yPgkxLLNg@mail.gmail.com \
    --to=benjamin.tissoires@redhat.com \
    --cc=blaz@mxxn.io \
    --cc=jikos@kernel.org \
    --cc=linux-input@vger.kernel.org \
    --subject='Re: HID: multitouch: Set to high latency mode on suspend.' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).