Re: [PATCH] ELAN touchpad i2c_hid bugs fix

From: Dmitry Torokhov <dtor@chromium.org>
To: Vladislav Dalechyn <vlad.dalechin@gmail.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>,
	Jiri Kosina <jikos@kernel.org>,
	kai.heng.feng@canonical.com, swboyd@chromium.org,
	bigeasy@linutronix.de,
	"open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	hotwater438@tutanota.com, Hans De Goede <hdegoede@redhat.com>
Subject: Re: [PATCH] ELAN touchpad i2c_hid bugs fix
Date: Mon, 25 Mar 2019 09:02:10 -0700	[thread overview]
Message-ID: <CAE_wzQ8Aep1FOONeCUxvjBFbgKcVRWP5mUuwQnDxzfemUw-eaA@mail.gmail.com> (raw)
In-Reply-To: <20190325125704.6585-1-hotwater438@tutanota.com>

Hi Vladislav,

On Mon, Mar 25, 2019 at 5:57 AM Vladislav Dalechyn
<vlad.dalechin@gmail.com> wrote:
>
> From: Vladislav Dalechyn <hotwater438@tutanota.com>
>
> Description: The ELAN1200:04F3:303E touchpad exposes several issues, all
> caused by an error setting the correct IRQ_TRIGGER flag:
> - i2c_hid incoplete error flood in journalctl;
> - Five finger tap kill's module so you have to restart it;
> - Two finger scoll is working incorrect and sometimes even when you
> raised one of two finger still thinks that you are scrolling.
>
> Fix all of these with a new quirk that corrects the trigger flag
> announced by the ACPI tables. (edge-falling).

I do not believe this is right solution. The driver makes liberal use
of disable_irq() and enable_irq() which may lead to lost edges and
touchpad stopping working altogether.

Usually the "extra" report is caused by GPIO controller clearing
interrupt condition at the wrong time (too early), or in unsafe or
racy fashion. You need to look there instead of adding quirk to
i2c-hid.

Thanks.

-- 
Dmitry