Re: [PATCH 1/5] m68k: Fix atari mouse movement

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Geert,

thanks for your review!

Am 14.08.2026 um 19:53 schrieb Geert Uytterhoeven:
> Hi Michael,
>
> CC linux-input
>
> On Fri, 14 Aug 2026 at 05:17, Michael Schmitz <schmitzmic@gmail.com> wrote:
>> From: Miro Kropacek <miro.kropacek@gmail.com>
>>
>> Kernels are built with -funsigned-char since version 6.2, resulting
>> in signed mouse position deltas getting misinterpreted as unsigned.
>>
>> Cast deltas passed in (unsigned) scancode buffer to correctly
>> interpret sign.
>>
>> Fixes: 3bc753c06dd02a35 ("kbuild: treat char as always unsigned")
>> Link: https://lists.debian.org/debian-68k/2026/08/msg00000.html
>> Signed-off-by: Miro Kropacek <miro.kropacek@gmail.com>
>> Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
>
> Since you're now in the path to upstream, you should add your SoB here
> (applies to all patches).
>
>> --- a/drivers/input/mouse/atarimouse.c
>> +++ b/drivers/input/mouse/atarimouse.c
>> @@ -70,9 +70,12 @@ static void atamouse_interrupt(char *buf)
>
> Alternative, you could change/restore the function's signature to take a
> "signed char *".

Agreed, but without a way to test this, I'd rather wait for Miro 
confirming that change also fixed the issue.

Cheers,

	Michael

>>         atari_mouse_buttons = buttons;
>>  #endif
>>
>> -       /* only relative events get here */
>> -       dx = buf[1];
>> -       dy = buf[2];
>> +       /* only relative events get here; the IKBD sends signed 8-bit
>> +        * deltas, and the kernel builds with -funsigned-char since 6.2,
>> +        * so an explicit signed cast is required
>> +        */
>> +       dx = (s8)buf[1];
>> +       dy = (s8)buf[2];
>>
>>         input_report_rel(atamouse_dev, REL_X, dx);
>>         input_report_rel(atamouse_dev, REL_Y, dy);
>
> Regardless:
> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
>