How to truly disable the write cache function(in dmesg) in Ubuntu for an external HDD?

I use sudo hdparm -W 0 /dev/sdb to disable the write cache for the HDD, and the information `/dev/sdb: write-caching = 0 (off)` shows that the write cache is truly off. But when I use the instruction sudo dmesg it shows that:

[23361.915713] sd 32:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

I see the write cache is still enabled, I would like to know how to truly disable the write cache function (in dmesg) in Ubuntu for an external HDD.