'What are implications of executing SCSI WRITE BUFFER with mode 0x0F when deferred microcode is not present on device

I am referring to SCSI SPC-5 (Scsi Primary Commands) Specification. While going through SCSI write buffer command (opcode=0x3B), I found various values for MODE field (0x04, 0x05, 0x0E, 0x0E .. and so on). To be specific, Spec mentions that Mode 0x0F will activate any deferred microcode and control information (if present) on device.

I have following questions around mode 0x0F,

  1. Can we also use write buffer scsi command with mode 0x0F to just reset expander device ? For example, If we don't have any deferred microcode and we are just sending above scsi command then what is expected behavior?
  2. If we can't use step(1) to reset expander device then is there any vendor independent way to perform an expander reset ?

Any information would be highly appreciated!

storagescsi


Solution 1:[1]

  1. No. If you don't have deferred code then it will not reset expander, only would return some information
  2. No universal way by SCSI command or likewise. However, difference SES device servers (you can think SES device server as the expander in your case) often have custom way to reset by SCSI command. For e.g., if you run this command "sg_senddiag --pf --raw=04,00,00,02,02,02 /dev/xxx" to expander, there is a chance that you reset the expander, because this is a very common custom way

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