mixer relative values don't work without a dev: bug or by design?

[Eitan Adler]

% mixer vol +4
Setting the mixer vol from 90:90 to 94:94.
% mixer vol -4
Setting the mixer vol from 94:94 to 90:90.
% mixer 95
Setting the mixer vol from 90:90 to 95:95.
% mixer 90
Setting the mixer vol from 95:95 to 90:90.

% mixer +5
---->Setting the mixer vol from 90:90 to 5:5.
% mixer -5
usage: mixer [-f device] [-s | -S] [dev [+|-][voll[:[+|-]volr]] ...
       mixer [-f device] [-s | -S] recsrc ...
       mixer [-f device] [-s | -S] {^|+|-|=}rec rdev ...
 devices: vol, bass, treble, pcm, mic, rec
 rec devices: mic


I have a patch that changes this so that the latter two commands work
like the first few and I'm wondering if this would be wanted?

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Eitan Adler