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Western Digital Hard Disk Drive OEM Specification
9.17.4 NCQ NON-DATA (63h)
The NCQ NON-DATA feature allows the host to manage the outstanding NCQ commands and/or affect the
processing of NCQ commands.
The NCQ NON-DATA command is a non-data NCQ command. Only specified NCQ NON-DATA subcommands are
executed as Immediate NCQ commands.
NCQ NON-DATA cmd, LBA fields should not be set to reserved.
LBA fields are optionally used in SetFeatures cmd.
If NCQ is disabled and an NCQ NON-DATA command is issued to the device, then the device aborts the command
with the ERR bit set to one in the Status register and the ABRT bit set to one in the Error register. This command is
prohibited for devices that implement the PACKET feature set. The queuing behavior of the device depends on
which subcommand is specified.
Table 41 NCQ NON-DATA - Command definition
Table 41 defines the Subcommand values. If an invalid subcommand is specified, then the device aborts the
command with the ERR bit set to one in the Status register, the ABRT bit set to one in the Error register, and causes
all outstanding commands to be aborted.
11.15.1 Abort NCQ Queue Subcommand (0h)
11.15.2 Deadline handling Subcommand (1h)
11.15.3 Set Features Subcommand (5h)
Table 42 Subcommand Field
Subcommand Specific (TTAG) is the selected queue TAG. This allows the host to select the specific outstanding
queued command to be managed.
The error and normal returns for this command are subcommand specific.
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