ioctl's and USB drives

[Leonard den Ottolander]

Hi Dragoran,

On Mon, 2005-08-08 at 09:25, dragoran wrote:
> Leonard den Ottolander wrote:
> >I noticed hdparm doesn't work well on external USB drives. Try a hdparm
> >-I /dev/sda and see it fail with a "HDIO_DRIVE_CMD(identify) failed:
> >Invalid argument". (I notice this on both a 2.4 and 2.6 kernel and with
> >hdparm-6.1.)
> >
> >My question is whether this is a shortcoming in the usb-storage driver,
> >or because of some shortcoming in the firmware of the external drive
> >(case). Or is it because the usb-storage driver uses emulated SCSI and
> >this is why these commands fail?

> hdparm -I only works on IDE devices on my sata drive it does not work 
> (/dev/sda1) but on the IDE drive (/dev/hda) it does.

So I assume it's the SCSI layer that is dropping these commands. Is
there a way to work around this by patching hdparm or do I have to hack
the kernel SCSI (emulation) layer to be able to send these commands?

Leonard.

-- 
mount -t life -o ro /dev/dna /genetic/research