Linux/DRA76P: make kernel continue after panic

Part Number:DRA76P

Tool/software: Linux

Hi all,

Our project adapt J6P(Dra76x) processor, with kernel 4.4.84. Our development boards' sound subsystem receive external reference clock as clock source.  By coincidence we found if the clock lose, kernel will panic and cycles most times while probe davinci_mcasp_probe and invoke __pm_runtime_idle, but occasionally kernel be able to pass the ridge and boot system success. In order to explicit the phenomenon, we 

cut off the reference clock line in hardware and found kernel can boot up indeed. 

So could anybody explain why it is, why kernel panic and cycles and why sometimes kernel can go over with just some warnings. Thanks.