View Full Version : SATA NQC question

26th August 2007, 05:27 AM

I have noticed something strange with me system. NCQ on my 36 gig WD raptor drive that I use for the OS (Fedora 7 64 bit) seems to be not enabled with my ASUS M2N32 WS Pro motherboard (Nvidia 590 chipset).

In dmesg I see this:

ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata1.00: ATA-7: WDC WD360ADFD-00NLR1, 20.07P20, max UDMA/133
ata1.00: 72303840 sectors, multi 1: LBA48 NCQ (depth 0/32)
ata1.00: configured for UDMA/133

This seem to indicate the the drive support a depth of 32 but NCQ is disabled.

Following the instructions form http://linux-ata.org/faq.html I issue the command:

echo 31 > /sys/block/sda/device/queue_depth

To which I got: -bash: /sys/block/sda/device/queue_depth: Permission denied

I notice this file didn't have write permission for root so I did a chmod +w and now I get: -bash: echo: write error: Input/output error when I run the above command.

So it seem I am unable to turn NCQing on for this drive.

hdparm seems to indicate this drive supports NCQ as well.

Does anyone know what is going on here? Any help or information greatly appreciated.

26th August 2007, 07:20 AM
Answered my own question. This drive is blacklisted as having a faulty NCQ implementation so NCQ is forced to be off by the kernel.

For more information: http://bugzilla.kernel.org/show_bug.cgi?id=8627