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From: Peter Hutterer <peter.hutterer@who-t.net>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Yariv <oigevald+kernel@gmail.com>, linux-input@vger.kernel.org
Subject: Re: PROBLEM: Apple external Trackpad event timestamps are jittery (regression)
Date: Tue, 12 May 2020 15:19:25 +1000	[thread overview]
Message-ID: <20200512051925.GA48688@koala> (raw)
In-Reply-To: <20200511201118.GW89269@dtor-ws>

On Mon, May 11, 2020 at 01:11:18PM -0700, Dmitry Torokhov wrote:
> Hi,
> 
> On Mon, May 11, 2020 at 09:18:15AM +0300, Yariv wrote:
> > Using a vanilla installation of Ubuntu 20.04 (kernel v5.4), the
> > timestamps of input events from my Apple "Magic Trackpad" - 1st
> > generation, connected over Bluetooth - are jittery.
> > This is a kernel regression. I bisected the bug.
> 
> Do you see the same jitter when connected over USB? Can you also see if
> there is similar jitter when you parse timestamps of SYN_RPEORT events
> from "evtest"?
> 
> Could you post a sample of events generated by device (via evtest)?

unrelated, but I really recommend using 'libinput record' these days since
it can be replayed (libinput replay) or analysed easier (it's YAML).
Also, it prints delta times into the recording so you can immediately check
those without having to parse them, e.g.:

  - evdev:
    - [  0, 375974,   2,   0,       5] # EV_REL / REL_X                     5
    - [  0, 375974,   2,   1,      -2] # EV_REL / REL_Y                    -2
    - [  0, 375974,   0,   0,       0] # ------------ SYN_REPORT (0) ---------- +8ms

Cheers,
   Peter


  reply	other threads:[~2020-05-12  5:19 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-11  6:18 PROBLEM: Apple external Trackpad event timestamps are jittery (regression) Yariv
2020-05-11 20:11 ` Dmitry Torokhov
2020-05-12  5:19   ` Peter Hutterer [this message]
2020-05-12 19:54     ` Yariv
2020-05-22  5:27       ` Yariv
2020-05-23 18:37         ` Dmitry Torokhov
2020-05-23 19:11           ` Yariv
2020-05-23 21:18             ` Dmitry Torokhov
2020-05-24 11:36               ` Yariv

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