Hi Chaps, Basically I detected this problem because I added another drive to my PCI SATA card, and now the system is running dog slow.
I tracked it down to one of the drives being forced into PIO4 mode rather than UDMA mode; dmesg bits: sata_nv 0000:00:0b.0: version 2.0 ACPI: PCI Interrupt Link [LSID] enabled at IRQ 11 PCI: setting IRQ 11 as level-triggered ACPI: PCI Interrupt 0000:00:0b.0[A] -> Link [LSID] -> GSI 11 (level, low) -> IRQ 11 PCI: Setting latency timer of device 0000:00:0b.0 to 64 ata1: SATA max UDMA/133 cmd 0x9F0 ctl 0xBF2 bmdma 0xE800 irq 11 ata2: SATA max UDMA/133 cmd 0x970 ctl 0xB72 bmdma 0xE808 irq 11 scsi0 : sata_nv ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) ata1.00: ATA-7, max UDMA/133, 586072368 sectors: LBA48 NCQ (depth 0/32) ata1.00: ata1: dev 0 multi count 16 ata1.00: configured for UDMA/133 scsi1 : sata_nv ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300) ata2.00: ATA-7, max UDMA/133, 586072368 sectors: LBA48 NCQ (depth 0/32) ata2.00: ata2: dev 0 multi count 16 ata2.00: configured for UDMA/133 scsi 0:0:0:0: Direct-Access ATA ST3300831AS 3.06 PQ: 0 ANSI: 5 SCSI device sda: 586072368 512-byte hdwr sectors (300069 MB) sda: Write Protect is off sda: Mode Sense: 00 3a 00 00 SCSI device sda: drive cache: write back SCSI device sda: 586072368 512-byte hdwr sectors (300069 MB) sda: Write Protect is off sda: Mode Sense: 00 3a 00 00 SCSI device sda: drive cache: write back sda: sda1 sda2 sd 0:0:0:0: Attached scsi disk sda sd 0:0:0:0: Attached scsi generic sg0 type 0 scsi 1:0:0:0: Direct-Access ATA ST3300831AS 3.06 PQ: 0 ANSI: 5 SCSI device sdb: 586072368 512-byte hdwr sectors (300069 MB) sdb: Write Protect is off sdb: Mode Sense: 00 3a 00 00 SCSI device sdb: drive cache: write back SCSI device sdb: 586072368 512-byte hdwr sectors (300069 MB) sdb: Write Protect is off sdb: Mode Sense: 00 3a 00 00 SCSI device sdb: drive cache: write back sdb: sdb1 sdb2 sd 1:0:0:0: Attached scsi disk sdb sd 1:0:0:0: Attached scsi generic sg1 type 0 sata_uli 0000:01:06.0: version 1.0 ACPI: PCI Interrupt 0000:01:06.0[A] -> Link [LNK3] -> GSI 10 (level, low) -> IRQ 10 ata3: SATA max UDMA/133 cmd 0x7000 ctl 0x7402 bmdma 0x8000 irq 10 ata4: SATA max UDMA/133 cmd 0x7800 ctl 0x7C02 bmdma 0x8008 irq 10 scsi2 : sata_uli ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300) ata3.00: ATA-7, max UDMA/133, 625142448 sectors: LBA48 NCQ (depth 0/32) ata3.00: ata3: dev 0 multi count 16 ata3.00: configured for UDMA/133 scsi3 : sata_uli ata4: SATA link up 1.5 Gbps (SStatus 113 SControl 300) ata4.00: ATA-7, max UDMA/133, 586072368 sectors: LBA48 NCQ (depth 0/32) ata4.00: ata4: dev 0 multi count 16 ata4.00: simplex DMA is claimed by other device, disabling DMA ata4.00: configured for PIO4 scsi 2:0:0:0: Direct-Access ATA ST3320620AS 3.AA PQ: 0 ANSI: 5 SCSI device sdc: 625142448 512-byte hdwr sectors (320073 MB) sdc: Write Protect is off sdc: Mode Sense: 00 3a 00 00 SCSI device sdc: drive cache: write back SCSI device sdc: 625142448 512-byte hdwr sectors (320073 MB) sdc: Write Protect is off sdc: Mode Sense: 00 3a 00 00 SCSI device sdc: drive cache: write back sdc: sdc1 sdc2 sd 2:0:0:0: Attached scsi disk sdc sd 2:0:0:0: Attached scsi generic sg2 type 0 scsi 3:0:0:0: Direct-Access ATA ST3300831AS 3.06 PQ: 0 ANSI: 5 SCSI device sdd: 586072368 512-byte hdwr sectors (300069 MB) sdd: Write Protect is off sdd: Mode Sense: 00 3a 00 00 SCSI device sdd: drive cache: write back SCSI device sdd: 586072368 512-byte hdwr sectors (300069 MB) sdd: Write Protect is off sdd: Mode Sense: 00 3a 00 00 SCSI device sdd: drive cache: write back sdd: sdd1 sdd2 sd 3:0:0:0: Attached scsi disk sdd sd 3:0:0:0: Attached scsi generic sg3 type 0 Why is ata4 reporting "simplex DMA is claimed by another device" and how can I get it to work correctly? Please let me know if you need more information. Cheers David - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/