Re: ATAPI burners support - significant regression in 5.x

> Date: Fri, 27 Aug 2004 22:05:13 +0300
> From: Maxim Sobolev <sobomax_at_portaone.com>
> Sender: owner-freebsd-current_at_freebsd.org
> 
> I've noticed that quality of support for ATAPI CD burners in 5.x has 
> degraded significantly. Often when burning CD-RW (I have not 
> experimented on CD-Rs for obvious reasons), burncd hangs in the middle, 
> without any error messages. When it happens it doesn't respond to 
> SIGKILL, eject button doesn't work and the only way to recover form this 
> situation without reboot is to run atacontrol reinit. I've tested 3 
> different CD-RW devices on 3 different machines (2 runnning RELENG_5 and 
> one running RELENG_5_2), and the same problem exists on all of them. All 
> machines were idle during my experiments.
> 
> The easy way to reproduce this problem is to create some dummy iso image 
> (e.g. dd if=/dev/random of=/tmp/tmp.iso bs=1m count=650), put blank 
> CD-RW medium into the burner and then run something along the lines:
> 
> while true; do time burncd -s max data /tmp/tmp.iso; burncd -s max 
> fixate; burncd -s max blank; sleep 5; done
> 
> I've tried RW mediums with various speed ratings: 2x-4x, 4x-12x, 16x-24x 
> the problem happens with all of them. It also makes no difference 
> whether the medium is new or used.
> 
> Turning DMA on or off doesn't solve the problem either.
> 
> All is matter of time - sooner or later burncd hangs solidly, usually 30 
> minutes is enough to reproduce the problem.
> 
> IMHO it is quite significant problem that have to be addressed before 
> the 5.3 is out. At least if I am not correct and the problem happens due 
> to  problems with particular CD-RW devices, ata driver has to be 
> "smarter" to recover from such situation gracefully, returning error 
> code and leaving device in the useable position.
> 
> I am ready to provide more information or assist with debugging if 
> necessary.

This is a "well known" problem that several people are looking into. So
far, no one has figured out exactly where the problem lies, but it is
known that a reset will get the drive running again. The ata software is
highly suspect, but I have not seen anything recent from sos_at_ about it.

What I do when it locks is to fire up some other program that will
access the CD. It picks up where it left off like nothing had
happened.  This is likely not the best solution, but it works on drives
with buffer underflow protection (which is most newer drives). 
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman_at_es.net			Phone: +1 510 486-8634