Using hdparm -d1 on the hard drives cause messages like this in dmesg. and occasional system lock ups. Kernel version 681 does not have any such messages in the log or lock up and IO ofcourse is significantly faster.
I am using yum for updating the kernels from the usual repositories
Jan 25 08:02:53 linux1 kernel: ICH: IDE controller at PCI slot 0000:00:1f.1
Jan 25 08:02:53 linux1 kernel: ICH: chipset revision 2
Jan 25 08:02:53 linux1 kernel: ICH: not 100% native mode: will probe irqs later
Jan 25 08:02:53 linux1 kernel: ide0: BM-DMA at 0xffa0-0xffa7, BIOS settings: hda:DMA, hdb:pio
Jan 25 08:02:53 linux1 kernel: ide1: BM-DMA at 0xffa8-0xffaf, BIOS settings: hdc:DMA, hdd:DMA
Jan 25 08:02:53 linux1 kernel: hda: Maxtor 30768H1, ATA DISK drive
Jan 25 08:02:53 linux1 kernel: Using cfq io scheduler
Jan 25 08:02:53 linux1 kernel: ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
Jan 25 08:02:53 linux1 kernel: hdc: WDC WD400AB-00CMB0, ATA DISK drive
Jan 25 08:02:53 linux1 kernel: hdd: LG CD-RW CED-8080B, ATAPI CD/DVD-ROM drive
Jan 25 08:02:53 linux1 kernel: ide1 at 0x170-0x177,0x376 on irq 15
Jan 25 08:02:53 linux1 kernel: hda: max request size: 128KiB
Jan 25 08:02:53 linux1 kernel: hda: 15007104 sectors (7683 MB) w/512KiB Cache, CHS=14888/16/63, UDMA(66)
Jan 25 08:02:53 linux1 kernel: hda: hda1 hda2
Jan 25 08:02:53 linux1 kernel: hdc: max request size: 128KiB
Jan 25 08:02:53 linux1 kernel: hdc: 78165360 sectors (40020 MB) w/2048KiB Cache, CHS=65535/16/63, UDMA(66)
Jan 25 08:02:53 linux1 kernel: hdc:hdc: dma_intr: status=0x51 { DriveReady SeekComplete Error }
Jan 25 08:02:53 linux1 kernel: hdc: dma_intr: error=0x84 { DriveStatusError BadCRC }
Jan 25 08:02:53 linux1 kernel: ide: failed opcode was: unknown
Jan 25 08:02:53 linux1 kernel: hdc: dma_intr: status=0x51 { DriveReady SeekComplete Error }
Jan 25 08:02:53 linux1 kernel: hdc: dma_intr: error=0x84 { DriveStatusError BadCRC }
Jan 25 08:02:53 linux1 kernel: ide: failed opcode was: unknown
....
Jan 25 08:02:53 linux1 kernel: drivers/ide/pci/piix.c:390: spin_lock(drivers/ide/ide.c:023728c8) already locked by drivers/ide/ide-iops.c/1246
Jan 25 08:02:53 linux1 kernel: hdd: DMA disabled
Jan 25 08:02:53 linux1 kernel: drivers/ide/ide-iops.c:1314: spin_unlock(drivers/ide/ide.c:023728c8) not locked
Jan 25 08:02:53 linux1 kernel: ide1: reset: success
Jan 25 08:02:53 linux1 kernel: hdc1 hdc2
