I am currently investigating an issue with the rcar-h2 audio driver and a hang when running pulse-audio. From what I can see the issue seems to be an interaction with the driver and the regmap code.

The current issue is that whatever is happening causes CPU0 to stall, thus nothing seems to be able to continue. The following errors are detected by the rcu code:

INFO: rcu_sched self-detected stall on CPU 0: (1 GPs behind) idle=415/2/0 softirq=3076/3077 (t=10500 jiffies g=520 c=519 q=51)

I have been through the regmap code and the locking looks ok. I also enabled as much of the locking checks as I could and it does not produce any useful output as to why it would be deadlocking.

I can run the system fine if I replace the rsnd_read, rsnd_write and rsnd_bset code with versions which do not directly use regmap.

Does anyone have any experience with this, or any further ideas on how to continue debugging?