linux-kernel - Re: [PATCH V2 3/3] Input: elantech - Fix incorrectly halved touchpad range on ELAN v3 touchpads

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Message-ID: <877cz6rncc.fsf@baylibre.com>
Date:   Mon, 05 Dec 2022 14:28:51 +0100
From:   Mattijs Korpershoek <mkorpershoek@...libre.com>
To:     Eirin Nya <nyanpasu256@...il.com>, phoenix <phoenix@....com.tw>
Cc:     'Dmitry Torokhov' <dmitry.torokhov@...il.com>,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        "'Josh.Chen'" <josh.chen@....com.tw>
Subject: Re: [PATCH V2 3/3] Input: elantech - Fix incorrectly halved
 touchpad range on ELAN v3 touchpads

Hi Eirin,

On Fri, Dec 02, 2022 at 23:42, Eirin Nya <nyanpasu256@...il.com> wrote:

>> If the setting is indeed double resolution, can we simply multiply 
>> x_max and y_max by 2 instead of re-querying it?
>
> Perhaps in some laptops, x_max or y_max is odd when resolution is
> doubled, and rounded up or down in half-resolution mode, so multiplying
> the half-resolution size by 2 results in a slightly incorrect full
> size. I don't know if that's the case in other touchpads, but my
> laptop's touchpad has even size in full-resolution (doubled) mode,
> meaning it doesn't round its size in half-resolution mode (so
> multiplying both values by 2 would work on my machine).
>
> On Wed, 30 Nov 2022 19:22:25 +0800
> "phoenix" <phoenix@....com.tw> wrote:
>
>> Consulted with FW team, we suggest re-querying x/y resolution after
>> setting absolute mode.
>
> My current patch re-queries x/y resolution after setting absolute mode.
> If this is the process that Elan's FW team recommends, should the patch
> be kept as-is?

Yes, I think you can keep it the way it is. Dmitry will either pick it
up or suggest additional changes.