Message-ID: <459AA01C.9090806@rtr.ca>
Date: Tue, 02 Jan 2007 13:10:36 -0500
From: Mark Lord <lkml@rtr.ca>
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To: Tejun Heo <htejun@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>, Rene Herman <rene.herman@gmail.com>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@osdl.org>
Subject: Re: 2.6.20-rc2+: CFQ halving disk throughput.
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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..
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