nv-sata: secondary device removed

I've been getting an usual error message, unusual in that in my 5 years of using Linux, I've *never* had my system crash. Ok, first off, the system works great sure, Firefox take a few seconds too long to boot, but hey), but when the system sits idle, I get a screen full of: nv_sata: secondary device removed nv_sata: secondary device added nv_sata: secondary device removed nv_sata: secondary device added ... And the machine locks up (no reponse to ALT CTRL BKSP) I've googled a bit, but most errors occur upon installation or boot. Any ideas?