Hello. I have done some quick tests with 2.6.23/amd64 and unfortunately, the very same problem persists. By the way, 8 in (port_status 0x20080000) stands for PDC_OVERRUN_ERR = (1 << 19), /* S/G byte count larger than HD requires */ Does by any chance 'S/G' here somehow relate to 'sg in the 'sg-chaining work' there is so much talk about on the -kernel mailing list? In a somewhat parallel development, write errors caused my (other) md RAID-1 to lose one drive while copying data under 2.6.22 from TX4-attached drives to onboard-VIA-attached ones. Device: VIA VT6420 00:0f.0 0104: 1106:3149 (rev 80) Boot: Oct 17 21:28:25 host sata_via 0000:00:0f.0: version 2.2 Oct 17 21:28:25 host ACPI: PCI Interrupt 0000:00:0f.0[B] -> GSI 20 (level, low) -> IRQ 17 Oct 17 21:28:25 host sata_via 0000:00:0f.0: routed to hard irq line 10 Oct 17 21:28:25 host scsi4 : sata_via Oct 17 21:28:25 host scsi5 : sata_via Oct 17 21:28:25 host ata6: SATA link up 1.5 Gbps (SStatus 113 SControl 300) Oct 17 21:28:25 host ata6.00: ATA-7: ST3200827AS, 3.AAH, max UDMA/133 Oct 17 21:28:25 host ata6.00: 390721968 sectors, multi 0: LBA48 NCQ (depth 0/32) Oct 17 21:28:25 host ata6.00: configured for UDMA/133 ... the first two port resets: Oct 17 23:10:50 host ata6.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x2 Oct 17 23:10:50 host ata6.00: (BMDMA stat 0x4) Oct 17 23:10:50 host ata6.00: cmd ca/00:08:e7:30:00/00:00:00:00:00/e0 tag 0 cdb 0x0 data 4096 out Oct 17 23:10:50 host res 51/84:08:e7:30:00/00:00:00:00:00/e0 Emask 0x10 (ATA bus error) Oct 17 23:10:50 host ata6: soft resetting port Oct 17 23:10:50 host ata6.00: configured for UDMA/133 Oct 17 23:10:50 host ata6: EH complete Oct 17 23:10:50 host sd 5:0:0:0: [sdd] 390721968 512-byte hardware sectors (200050 MB) Oct 17 23:10:50 host sd 5:0:0:0: [sdd] Write Protect is off Oct 17 23:10:50 host sd 5:0:0:0: [sdd] Mode Sense: 00 3a 00 00 Oct 17 23:10:50 host sd 5:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Oct 17 23:10:50 host ata6.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x2 Oct 17 23:10:50 host ata6.00: (BMDMA stat 0x5) Oct 17 23:10:50 host ata6.00: cmd ca/00:f8:4f:31:00/00:00:00:00:00/e0 tag 0 cdb 0x0 data 126976 out Oct 17 23:10:50 host res 51/84:f8:4f:31:00/00:00:00:00:00/e0 Emask 0x10 (ATA bus error) Oct 17 23:10:50 host ata6: soft resetting port Oct 17 23:10:50 host ata6.00: configured for UDMA/133 Oct 17 23:10:50 host ata6: EH complete Oct 17 23:10:50 host sd 5:0:0:0: [sdd] 390721968 512-byte hardware sectors (200050 MB) Oct 17 23:10:50 host sd 5:0:0:0: [sdd] Write Protect is off Oct 17 23:10:50 host sd 5:0:0:0: [sdd] Mode Sense: 00 3a 00 00 Oct 17 23:10:50 host sd 5:0:0:0: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA ... and multiple unsuccessful port resets follow: Oct 17 23:11:57 host ata6.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x2 frozen Oct 17 23:11:57 host ata6.00: cmd 25/00:08:7f:bf:28/00:00:16:00:00/e0 tag 0 cdb 0x0 data 4096 in Oct 17 23:11:57 host res 40/00:f8:4f:31:00/00:00:00:00:00/e0 Emask 0x4 (timeout) Oct 17 23:12:02 host ata6: port is slow to respond, please be patient (Status 0xd0) Oct 17 23:12:07 host ata6: soft resetting port Oct 17 23:12:37 host ata6.00: qc timeout (cmd 0xec) Oct 17 23:12:37 host ata6.00: failed to IDENTIFY (I/O error, err_mask=0x4) Oct 17 23:12:37 host ata6.00: revalidation failed (errno=-5) Oct 17 23:12:37 host ata6: failed to recover some devices, retrying in 5 secs Oct 17 23:12:47 host ata6: port is slow to respond, please be patient (Status 0xd0) Oct 17 23:12:52 host ata6: soft resetting port Oct 17 23:13:22 host ata6.00: qc timeout (cmd 0xec) Oct 17 23:13:22 host ata6.00: failed to IDENTIFY (I/O error, err_mask=0x4) Oct 17 23:13:22 host ata6.00: revalidation failed (errno=-5) Oct 17 23:13:22 host ata6.00: limiting speed to UDMA/133:PIO3 Oct 17 23:13:22 host ata6: failed to recover some devices, retrying in 5 secs Oct 17 23:13:32 host ata6: port is slow to respond, please be patient (Status 0xd0) Oct 17 23:13:37 host ata6: soft resetting port Oct 17 23:14:08 host ata6.00: qc timeout (cmd 0xec) Oct 17 23:14:08 host ata6.00: failed to IDENTIFY (I/O error, err_mask=0x4) Oct 17 23:14:08 host ata6.00: revalidation failed (errno=-5) Oct 17 23:14:08 host ata6.00: disabled Oct 17 23:14:08 host ata6: EH complete Oct 17 23:14:08 host sd 5:0:0:0: [sdd] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK,SUGGEST_OK Oct 17 23:14:08 host end_request: I/O error, dev sdd, sector 371769215 Oct 17 23:14:08 host raid1: sdd1: rescheduling sector 371769152 Oct 17 23:14:08 host sd 5:0:0:0: [sdd] Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK,SUGGEST_OK Oct 17 23:14:08 host end_request: I/O error, dev sdd, sector 390379327 Oct 17 23:14:08 host md: super_written gets error=-5, uptodate=0 Oct 17 23:14:08 host raid1: Disk failure on sdd1, disabling device. I'm unable to reproduce this on 2.6.23, so this is of historic interest only. -- ./lxnt - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html