> On 22. 4. 2022, at 13:19, Mark Brown <broonie@xxxxxxxxxx> wrote: > > On Fri, Apr 22, 2022 at 12:43:30PM +0200, Martin Povišer wrote: > >> I looked in the TAS2770 and TAS2764 drivers/datasheets, and to answer >> the questions we had: > >> * VSENSE/ISENSE output slots are configured independently of audio samples >> routing. Kernel drivers configure the slots based on the 'ti,imon-slot-no' >> and 'ti,vmon-slot-no' properties of devicetree. > >> * By default codecs transmit Hi-Z for duration of unused slots. > >> So once we supply the devicetree props it should be electrically sound >> under any configuration of userspace knobs. > > Great, that's a relief. > >> One final thought on the playback routing controls: On systems with >2 >> speakers, the codecs need to be assigned slots through set_tdm_slot. >> The macaudio driver RFCed here assigns a single slot to each speaker, >> making the effect of each speaker's routing control this: > >> 'I2C offset' -- uses a random slot > >> 'Left' 'Right' 'LeftRight' -- uses the single slot we configured > >> I suppose I better assign two slots to speakers in each left-right pair >> of the same kind (e.g. woofer 1, woofer 2, tweeter). This way the >> routing control will mimic its behavior from simple stereo systems but >> replicated within each left-right pair. (I would prefer to hide the >> controls altogether, but as I learned that hiding things unless proven >> dangerous is an ASoC non-goal, this way I can make the controls do >> something interesting.) > > I don't quite grasp the difference between the arrangement you're > proposing and assigning a single slot to each speaker? Possibly it's > just a reordering of the slots? Ah, maybe what’s missing is the fact that the way the speaker amp drivers are written, if they are assigned two slots with a call to set_tdm_slot, the first slot is considered 'left' and the second is 'right'. So in the arrangement I am proposing the 'Left', 'Right' and 'LeftRight' values of the routing control have the nominal effect (within the left-right speaker pair), while in the other arrangement it is as I described above.
