[alsa-devel] bug in playing 6-channel sound

[Julian Bradfield]

Some five years ago, the following post

https://mailman.alsa-project.org/pipermail/alsa-devel/2014-February/072265.html

reported a failure to play six-channel sound, that could be worked
around by setting the prealloc value for the device to various values
*other than* the default 64. 

I have just run into this playing a movie from my laptop (Thinkpad
Yoga X1, Intel HDA PCH sound card outputting through HDMI) running
Xubuntu 18.04, up to date as at the time of posting.

I see exactly the same problem as in that post, and the same
workaround works for me - I tried prealloc values 63,65,32,128, and
any of them is ok.

I'm a bit baffled that such a problem has survived for several years.

If any developer would like me to provide debugging information,
please get in touch - I have some time available at present, but not
enough to learn ALSA and debug it myself!

I will remain subscribed to the list for a few weeks to read any
followups.