Edit: Problem solved. Apparently this was caused by a firmware mismatch or insufficient firmware files in /lib/firmware/intel . To be sure you are using the correct firmware, uninstall linux-firmware, and be sure there is nothing remaining in /lib/firmware/intel. Finally copy the contents of the chromium repo (click tgz to download) to /lib/firmware/intel. You should see an audio device on next boot.
I am testing an Intel Bay Trail Tablet running Kernel 3.16.2 from the Ubuntu mainline PPA with linux-firmware installed and up to date. I need this kernel or newer for working wireless. I see this error in dmesg and sound is not working:
The file that ships with ubuntu in the linux-firmware package is named "fw_sst_0f28.bin-48kHz_i2s_master" instead. This is also the name of the file in the official linux firmware git tree: http://git.kernel.org/cgit/linux/ker...kHz_i2s_master . This is another one with the original naming I found referenced on this forum: https://chromium.googlesource.com/ch...-5339.B/intel/ .
I can either rename the original, rename the official, or use the Google version but they all result in the same error on the next boot. Several instances of:
byt-rt5640 byt-rt5640: ASoC: CPU DAI baytrail-pcm-audio not registered
This post on xda developers talks a little about what I am trying to do: http://forum.xda-developers.com/show...&postcount=370
baytrail-pcm-audio baytrail-pcm-audio: ipc: error DSP boot timeout
Where can I go from here?