what does this mean? "soft resetting link" in messages

One of my slackware computer is logging these in messages and something similar in syslog, a few line everyday or so. Using slackware 64 stable, up to date.

Quote:

Oct 11 21:01:31 slakbox kernel: [1654983.785060] ata4: soft resetting link Oct 11 21:01:31 slakbox kernel: [1654983.942335] ata4.00: configured for UDMA/133 Oct 11 21:01:31 slakbox kernel: [1654983.942347] ata4: EH complete

Code:smartctl -a /dev/sdcReports a bit of info, what ID#, ATTRIBUTE_NAME, RAW_VALUE might be relevant?

I replaced the data cables with new ones a month or so ago, as I keep finding posts on web that suggest this isn't a drive problem, the drive is newer from about March this year.

Thank you