On Thu, May 02, 2019 at 05:59:17PM +0900, Akinobu Mita wrote: > This enables to capture snapshot of controller information via device > coredump machanism, and it helps diagnose and debug issues. > > The nvme device coredump is triggered before resetting the controller > caused by I/O timeout, and creates the following coredump files. > > - regs: NVMe controller registers, including each I/O queue doorbell > registers, in nvme-show-regs style text format.
You're supposed to treat queue doorbells as write-only. Spec says: The host should not read the doorbell registers. If a doorbell register is read, the value returned is vendor specific.