Comment 28 for bug 1539209

https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound?id=2d3391ec0ecca37efb6bc995906292f47522b471

The difference between std channel map and alt channel map

You need to modify the driver by adding lines without "+" at the end of the two routines

+ err = snd_pcm_add_chmap_ctls(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+ snd_pcm_alt_chmaps, cm->max_channels, 0,
+ NULL);
+ if (err < 0)
+ return err;
+