Re: [RFC] tty/sysrq: Add alternative SysRq key

[Andrzej Pietrasiewicz]

Hi,

W dniu 04.11.2021 o 15:17, Andrzej Pietrasiewicz pisze:
> Hi Maciej,
>
> W dniu 04.11.2021 o 14:13, Maciej W. Rozycki pisze:
> > On Thu, 4 Nov 2021, Maciej W. Rozycki wrote:
> >
> > >   The reason for this is with their more recent laptops Lenovo in their
> > > infinite wisdom have placed the <PrintScreen> key (which in a traditional
> > > PS/2-keyboard manner produces <SysRq> when combined with <Alt>) in their
> > > keyboards between the right <Alt> and <Ctrl> keys.  With thumbs not being
> > > as accurate as other fingers (and the overall misdesign of the keyboard
> > > and touchpad interface) you can imagine how often I have inadvertently hit
> > > <SysRq> combined with a letter key, wreaking havoc to my system (and of
> > > course I want to keep the key enabled for times when I do need it).
> >
> >   On second thoughts this can be disabled with `setkeycodes 54 0' once we
> > do have an alternative combination available.
>
> Doesn't `setkeycodes` affect only one keyboard? What if there are more
> keyboards connected to a machine?
>
>  From drivers/tty/vt/keyboard.c:
>
> /*
>   * Translation of scancodes to keycodes. We set them on only the first
>   * keyboard in the list that accepts the scancode and keycode.
>   * Explanation for not choosing the first attached keyboard anymore:
>   *  USB keyboards for example have two event devices: one for all "normal"
>   *  keys and one for extra function keys (like "volume up", "make coffee",
>   *  etc.). So this means that scancodes for the extra function keys won't
>   *  be valid for the first event device, but will be for the second.
>   */

My second thoughts: if we run `setkeycodes` to map, say, F10 as SysRq,
don't we lose F10?

Andrzej