As one of the most expensive SSD drives available on the market, it was disconcerting to find dmesg -T showing trim errors, when the drive was mounted with the discard option. Research on mailing lists, indicated that the driver devs, believe it's a Samsung firmware issue.
Disabling trim in fstab, stopped the error messages. However it's difficult to get good information about whether drive performance or longevity may be impacted without the trim support.