https://bugs.freedesktop.org/show_bug.cgi?id=106957
--- Comment #5 from Lukas Wunner lukas@wunner.de --- Okay the HDA's runtime ref counter is 0 and it has no active children, so it should suspend. Chances are it doesn't because rpm_idle() fails for some reason.
Could you try this debug patch that I had created for #106597 and post the dmesg output?
https://bugs.freedesktop.org/attachment.cgi?id=139706&action=edit
You can add "log_buf_len=10M ignore_loglevel" to the command line to ensure that dmesg isn't truncated and contains all debug output.