dm suspend says "send_SuspendToRam: Failure with error: ZX_ERR_NOT_SUPPORTED"

[nealmcb]

Qemu is a real CPU hog for natural reasons. It would be nice to be able to pause or suspend Fuchsia / Zircon.

My first attempt was simply to use the Linux shell suspend approach (ctrl-z), but if you wait more than a few seconds to put the process back in the foreground, it crashes:

ZIRCON KERNEL OOPS                                                                                           
lockup_detector: no heartbeat from CPU-1 in 42506438 ms, last_heartbeat=520344414253 observed now=43026782921300 name=unknown.

Reported by [CPU-2] (message rate limited)
ZIRCON KERNEL PANIC
timer_ints: 146242, interrupts: 0

        tweight=0.2952270507 nfair=7 ndeadline=0 vtime=180747885048 period=8 tema=12583943 tutil=0.0
UPTIME: 43026795ms

I was happy to see a dm suspend command, but it says:

[00031.044] 21072:21074> [shutdown-shim]: checking power_manager liveness
send_SuspendToRam: Failure with error: ZX_ERR_NOT_SUPPORTED[00031.065]
 21072:21074> [shutdown-shim]: trying to forward command

What would it take to support SuspendToRam in this environment?

Are there other ways to pause the emulation and resume quickly?

[nmcain]

ZX_ERR_NOT_SUPPORTED seems to indicate that the feature isn't finished on Google's end. I'll be sure to check this in newer revisions of Fuchsia.