[smartmontools-support] Explanation of "Supported Power States" entries for NVMe devices

[Christian Franke]

Steven Foucault wrote:
> I was checking a NVMe device via smartmontools and found the “Supported Power States” entry.
> Unfortunately I wasn’t able to find an explanation for the data columns. (Op, Active, Idle, RL, RT, WL,WT, Ent_Lat, Ex_Lat).
>
> Where can I find information to this values (what do they mean)? Or could someone on this list give a short overview?

See "Identify – Power State Descriptor Data Structure" in NVMe specs:
https://nvmexpress.org/resources/specifications/
In NVM Express 1.3c, it is "Figure 112" at page 142.

The mapping of column names to abbreviations in the standard is as follows:
Op: ! NOP
Active: ACTP * APS
Idle: IDLP * IPS
RL: RRL
RT: RRT
WL: RWL
WT: RWT
Ent_Lat: ENLAT
Ex_Lat: EXLAT


Thanks,
Christian