On Fri, Apr 21, 2023 at 10:55:23AM +0200, Takashi Iwai wrote:
right, i didn't mention it, but i imagined the strings to remain the same, both for backwards compat, and because they serve a "label" function regardless of semantic interpretation. of course that would make them partially redundant with the newly added bits, but that doesn't seem too bad to me.i suppose we'd have to add SNDRV_CTL_ELEM_ACCESS_{PLAYBACK,CAPTURE}. both could be set for unspecific and actually bidirectional controls. if neither is set, user space would fall back to the keyword based rules (and exceptions ...) - that would be backwards compatible and would enable a gradual migration.The backward compatibility isn't really easy as you wrote, I'm afraid. If you run an old user-space stuff on the new kernel, you must not fill that new information bit but translate it to the string suffix instead; and that has to be done inside the kernel automagically.
anyway, i think i have enough background info now to write a nice paragraph for the docu.
thanks!
