Re: 2.6.20-rc2+: CFQ halving disk throughput.

Mark Lord
2007-01-02T18:10:39Z

Tejun Heo wrote:
> Mark Lord wrote:
>
>>> Support for IDENTIFY PACKET DEVICE would be nice too.
>> It already does that, using HDIO_DRIVE_CMD to retrieve it
>> in the same way as for regular IDENTIFY DEVICE commands.
>
> Hmmm... My hdparm doesn't seem to do that.

Sure it does.
Try "strace hdparm -I /dev/sr0" and notice the two ioctl() calls.

The problem is that libata/SCSI always fail it for some reason.
Ditto for me right now when I tried it with an SG_IO passthru command.

Contrary to my other posting, I actually *do* have a libata-controlled
DVD/RW drive in my box here. So I'll try and see what's happening.

Still digging..