Unable to change sata NCQ depth due to readonly /sys/block/sdc/device/queue_depth file

["Roy Franz" <roy.lists@gmail.com>]

Hi,

 I am unable to change the NCQ settings for a sata drive that
supports it - NCQ is always on.  This is due to the sysfs queue_depth
file being read-only.  This is on
vanilla 2.6.21.5 running with Debian Etch.  (Several earlier versions
of the kernel
had this same issue.)  The drive (WD Raptor) is hooked up to a Nvidia
sata controller.

amd64:/# ls -al /sys/block/sdc/device/queue_depth
-r--r--r-- 1 root root 4096 2007-06-28 10:04 /sys/block/sdc/device/queue_depth
amd64:/# cat /sys/block/sdc/device/queue_depth
31
amd64:/#

I searched but did not find any helpful information on this.  Forcing
a change by changing permissions on the file did not work.

Thanks,
Roy
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/