CMD_CLEARCACHE with not empty display list

[Rudolph]

I am experimenting with making EVE cry in order to test recovering from co-processor faults.

And this might be one for the Bridgetek bug-tracker.
It takes over 12ms from issuing CMD_CLEARCACHE to getting a co-processor fault.
When reading REG_CMDB_SPACE 12ms after CMD_CLEARCACHE is done the result is 0x0FF8.
When reading REG_CMDB_SPACE 13ms after CMD_CLEARCACHE is done the result is 0x0FC3.

In contrast I am getting a co-processor fault after 20µs when issuing EVE_cmd_setscratch(43), did not check how fast actually.

I do not have an issue with CMD_CLEARCACHE, for one it is documented that the display list needs to be empty, my function EVE_cmd_clearcache() clears out both of the display list before issuing CMD_CLEARCACHE and then I can not recall that I ever used this command.
I just found this peculiar and perhaps this is something worth looking into.