Problems with one of my ATA channels

syslog

Aug 18 19:06:06 thor kernel: [102499.392524] ata4.00: exception Emask 0x10 SAct 0x800200 SErr 0x400000 action 0x6 frozen
Aug 18 19:06:06 thor kernel: [102499.392530] ata4.00: irq_stat 0x08000000, interface fatal error
Aug 18 19:06:06 thor kernel: [102499.392534] ata4: SError: { Handshk }
Aug 18 19:06:06 thor kernel: [102499.392537] ata4.00: failed command: READ FPDMA QUEUED
Aug 18 19:06:06 thor kernel: [102499.392542] ata4.00: cmd 60/f0:48:00:60:ac/00:00:a6:00:00/40 tag 9 ncq 122880 in
Aug 18 19:06:06 thor kernel: [102499.392542]          res 40/00:bc:00:b4:ac/00:00:a6:00:00/40 Emask 0x10 (ATA bus error)
Aug 18 19:06:06 thor kernel: [102499.392545] ata4.00: status: { DRDY }
Aug 18 19:06:06 thor kernel: [102499.392548] ata4.00: failed command: WRITE FPDMA QUEUED
Aug 18 19:06:06 thor kernel: [102499.392552] ata4.00: cmd 61/00:b8:00:b4:ac/04:00:a6:00:00/40 tag 23 ncq 524288 out
Aug 18 19:06:06 thor kernel: [102499.392552]          res 40/00:bc:00:b4:ac/00:00:a6:00:00/40 Emask 0x10 (ATA bus error)
Aug 18 19:06:06 thor kernel: [102499.392554] ata4.00: status: { DRDY }
Aug 18 19:06:06 thor kernel: [102499.392559] ata4: hard resetting link
Aug 18 19:06:06 thor kernel: [102499.884130] ata4: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Aug 18 19:06:06 thor kernel: [102499.896896] ata4.00: configured for UDMA/133
Aug 18 19:06:06 thor kernel: [102499.912072] ata4: EH complete
Aug 18 19:06:09 thor kernel: [102502.913092] ata4.00: exception Emask 0x10 SAct 0xc00 SErr 0x400000 action 0x6 frozen
Aug 18 19:06:09 thor kernel: [102502.913102] ata4.00: irq_stat 0x08000000, interface fatal error
Aug 18 19:06:09 thor kernel: [102502.913108] ata4: SError: { Handshk }
Aug 18 19:06:09 thor kernel: [102502.913114] ata4.00: failed command: WRITE FPDMA QUEUED
Aug 18 19:06:09 thor kernel: [102502.913123] ata4.00: cmd 61/00:50:c0:07:b0/04:00:a6:00:00/40 tag 10 ncq 524288 out
Aug 18 19:06:09 thor kernel: [102502.913123]          res 40/00:5c:c0:0b:b0/00:00:a6:00:00/40 Emask 0x10 (ATA bus error)
Aug 18 19:06:09 thor kernel: [102502.913128] ata4.00: status: { DRDY }
Aug 18 19:06:09 thor kernel: [102502.913132] ata4.00: failed command: WRITE FPDMA QUEUED
Aug 18 19:06:09 thor kernel: [102502.913140] ata4.00: cmd 61/40:58:c0:0b:b0/00:00:a6:00:00/40 tag 11 ncq 32768 out
Aug 18 19:06:09 thor kernel: [102502.913140]          res 40/00:5c:c0:0b:b0/00:00:a6:00:00/40 Emask 0x10 (ATA bus error)
Aug 18 19:06:09 thor kernel: [102502.913144] ata4.00: status: { DRDY }
Aug 18 19:06:09 thor kernel: [102502.913151] ata4: hard resetting link
Aug 18 19:06:10 thor kernel: [102503.404075] ata4: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Aug 18 19:06:10 thor kernel: [102503.418334] ata4.00: configured for UDMA/133
Aug 18 19:06:10 thor kernel: [102503.432170] ata4: EH complete