On Mon, Dec 05, 2022 at 11:01:12PM +0000, Chris Down wrote:
> It's not uncommon for one keysym to map to multiple keycodes. For
> example, the "play" button on my keyboard sends keycode 172, but my
> bluetooth headphones send keycode 208, both of which map back to
> XF86AudioPlay:
>
> % xmodmap -pke | grep XF86AudioPlay
> keycode 172 = XF86AudioPlay XF86AudioPause XF86AudioPlay XF86AudioPause
> keycode 208 = XF86AudioPlay NoSymbol XF86AudioPlay
> keycode 215 = XF86AudioPlay NoSymbol XF86AudioPlay
>
> This is a problem because the current code only grabs a single one of
> these keycodes, which means that events for any other keycode also
> mapping to the bound keysym will not be handled by dwm. In my case, this
> means that binding XF86AudioPlay does the right thing and correctly
> handles my keyboard's keys, but does nothing on my headphones. I'm not
> the only person affected by this, there are other reports[0].
>
> In order to fix this, we look at the mappings between keycodes and
> keysyms at grabkeys() time and pick out all matching keycodes rather
> than just the first one. The keypress() side of this doesn't need any
> changes because the keycode gets converted back to a canonical keysym
> before any action is taken.
>
> 0: https://github.com/cdown/dwm/issues/11
> ---
> dwm.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/dwm.c b/dwm.c
> index 253aba7..af75787 100644
> --- a/dwm.c
> +++ b/dwm.c
> _AT_@ -955,16 +955,24 @@ grabkeys(void)
> {
> updatenumlockmask();
> {
> - unsigned int i, j;
> + unsigned int i, j, k;
> unsigned int modifiers[] = { 0, LockMask, numlockmask, numlockmask|LockMask };
> - KeyCode code;
> + int start, end, skip;
> + KeySym *syms;
>
> XUngrabKey(dpy, AnyKey, AnyModifier, root);
> - for (i = 0; i < LENGTH(keys); i++)
> - if ((code = XKeysymToKeycode(dpy, keys[i].keysym)))
> - for (j = 0; j < LENGTH(modifiers); j++)
> - XGrabKey(dpy, code, keys[i].mod | modifiers[j], root,
> - True, GrabModeAsync, GrabModeAsync);
> + XDisplayKeycodes(dpy, &start, &end);
> + syms = XGetKeyboardMapping(dpy, start, end - start + 1, &skip);
> + for (k = start; k <= end; k++)
> + for (i = 0; i < LENGTH(keys); i++)
> + /* skip modifier codes, we do that ourselves */
> + if (keys[i].keysym == syms[(k - start) * skip])
> + for (j = 0; j < LENGTH(modifiers); j++)
> + XGrabKey(dpy, k,
> + keys[i].mod | modifiers[j],
> + root, True,
> + GrabModeAsync, GrabModeAsync);
> + XFree(syms);
> }
> }
>
> --
> 2.38.1
>
>
Hi Chris,
Thanks for the patch, I will probably look at it further this weekend.
Should syms be checked before XFree(syms) or can the return value not be NULL?
If others are willing to test it also and report if this breaks something
please do so,
--
Kind regards,
Hiltjo
Received on Wed Dec 07 2022 - 09:33:23 CET