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From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Yariv <oigevald+kernel@gmail.com>
Cc: linux-input@vger.kernel.org
Subject: Re: PROBLEM: Apple external Trackpad event timestamps are jittery (regression)
Date: Sat, 23 May 2020 11:37:34 -0700
Message-ID: <20200523183734.GC89269@dtor-ws> (raw)
In-Reply-To: <CAEwx+QowRY3UTkFcwFvOD3h0=ejZSLL3miFQzdOMNT84w86M6g@mail.gmail.com>

Hi,

On Fri, May 22, 2020 at 08:27:43AM +0300, Yariv wrote:
> 
> Some things I noticed: Gen2 didn't send "BTN_TOOL_FINGER" events,
> while Gen1 did, even though I did not press any button. Note that Gen1
> still had correct timestamps before the regression, even though it
> sent these events.
> 
> Another difference (maybe it's the same one..): if you take a look at
> the logs from my previous mail, you'll notice that Gen1 Trackpads
> always send both SYN_REPORT (0) as well as SYN_REPORT (1), while 2nd
> Gen Trackpads only sends SYN_REPORT (0).

So it looks like for Gen1 touchpads we set autorepeat, and it is that
autorepeat on BTN_TOOL_FINGER that gives what you consider jitter.

  - evdev:
    - [  0, 293648,   1, 325,       2] # EV_KEY / BTN_TOOL_FINGER           2
    - [  0, 293648,   0,   0,       1] # ------------ SYN_REPORT (1) ---------- +1ms
  - evdev:
    - [  0, 303026,   3,  48,      88] # EV_ABS / ABS_MT_TOUCH_MAJOR       88 (-12)
    - [  0, 303026,   3,  53,    -232] # EV_ABS / ABS_MT_POSITION_X      -232 (-22)
    - [  0, 303026,   3,  54,     291] # EV_ABS / ABS_MT_POSITION_Y       291 (+60)
    - [  0, 303026,   3,   0,    -232] # EV_ABS / ABS_X                  -232 (-22)
    - [  0, 303026,   3,   1,     291] # EV_ABS / ABS_Y                   291 (+60)
    - [  0, 303026,   0,   0,       0] # ------------ SYN_REPORT (0) ---------- +10ms

Can you please tell me what drivers are used by the 2 trackpads when they
are connected via Bluetooth? I think we should stop setting autorepeat in
the driver that handles Gen 1.

Also, can you post /proc/bus/input/devices?

Thanks.

-- 
Dmitry

  reply index

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

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