[BUG] start/stop of SSP/nodec stream interferes with another stream

[kv2019i]

Describe the bug
This is a clone of Linux bug thesofproject/linux#854
The history is a bit complex to follow, but upon study of the bug today, the case is as follows:

Two PCM playback clients connected to SSP in nocodec mode. One client is kept stream, while other continuously starts and stops.

To Reproduce
Aplay instructions in
thesofproject/linux#854 (comment)

Reproduction Rate
1/10

Expected behavior
Starting and stopping one stream does not interfere with another stream.

Impact
End-product cases with multiple pipelines will show errors (e.g. a UI sound feedback may interfere with HDMI output).

Environment
APL UP2 pcm512x & APL UP2 nocodec
sof (master): 92fc706
kernel (topic/sof-dev): 80a2cb8
topology: sof-apl-pcm512x.tplg & sof-apl-nocodec.tplg

Screenshots or console output
See thesofproject/linux#854 (comment)

[kv2019i]

soflog.txt

Annotated bits from above log.
client 1 (all the time running) is started

    0      2         PIPE 14.62   2799191127.291667        22.031250 src/audio/pipeline.c:607 	pipeline_trigger()
    0      2         HOST         2799191131.406250         4.114583     src/audio/host.c:262 	host_trigger()
    0      2          DMA         2799191135.572917         4.166667 intel/cavs/hda-dma.c:531 	hda-dmac: 5 channel 1 -> start
    0      2          DMA         2799191139.218750         3.645833 intel/cavs/hda-dma.c:367 	hda-dmac: 5 channel 1 -> enable
    0      2       VOLUME         2799191176.510417        37.291668 udio/volume/volume.c:464 	volume_trigger()
    0      2          SRC         2799191180.468750         3.958333  src/audio/src/src.c:682 	src_trigger()
    0      2        MIXER         2799191184.479167         4.010417    src/audio/mixer.c:211 	mixer_trigger()
    0      2         COMP         2799191187.916667         3.437500 rc/audio/component.c:105 	comp_set_state(), state already set to 5

Then client 2 (start/stop in loop) is stopped and started and start fails

    0      2         PIPE 1.9     2817044901.093750       166.718750 src/audio/pipeline.c:378 	pipeline_prepare()
    0      2         HOST         2817044905.052083         3.958333     src/audio/host.c:614 	host_prepare()
    0      2       VOLUME         2817044918.489583        13.437500 udio/volume/volume.c:522 	volume_prepare()
    0      2        MIXER         2817044931.770833        13.281250    src/audio/mixer.c:358 	mixer_prepare()
    0      1         COMP         2817045834.635417       902.864563 rc/audio/component.c:237 	comp_get_copy_limits() error: sink component buffer has not enough free bytes for copy
    0      2         COMP         2817045840.156250         5.520833 of/audio/component.h:726 	comp_overrun(), ((dev->comp.id << 16) | sink->free) = 131072, 

Xrun recovery fails for client 2, but that also brings down client 1:

    0      2         PIPE 14.62   2817439722.968750        21.041666 src/audio/pipeline.c:607 	pipeline_trigger()
    0      2         HOST         2817439726.770833         3.802083     src/audio/host.c:262 	host_trigger()
    0      2          DMA         2817439730.833333         4.062500 intel/cavs/hda-dma.c:626 	hda-dmac: 5 channel 1 -> stop
    0      2       VOLUME         2817439735.156250         4.322917 udio/volume/volume.c:464 	volume_trigger()
    0      2          SRC         2817439739.062500         3.906250  src/audio/src/src.c:682 	src_trigger()
    0      2        MIXER         2817439742.812500         3.750000    src/audio/mixer.c:211 	mixer_trigger()
    0      2          IPC         2817439894.218750       151.406250    src/ipc/handler.c:328 	ipc: comp 56 -> free
    0      2         PIPE 14.62   2817439915.260417        21.041666 src/audio/pipeline.c:686 	pipeline_reset()

[lgirdwood]

@kv2019i are these two pipelines connected via the mixer ? or are they not connected. Just confused seeing HDMI and SSP then seeing MIXER in the logs.

[kv2019i]

@lgirdwood wrote:

@kv2019i are these two pipelines connected via the mixer ? or are they not connected. Just confused seeing HDMI and SSP then seeing MIXER in the logs.

Good point, yes they are. This is the standard pipe of:
https://github.com/thesofproject/sof/blob/master/tools/topology/sof-apl-nocodec.m4

Updated the title to reflect this related to two streams connected via mixer.

[tlauda]

@kv2019i Fail happens when you are stopping client 0 and client 1 is running. As long as you are stopping client 1 everything is working. It doesn't really matter, because it's still a bug, but just wanted to make sure you are aware of that.