ATA DVD playback hanging in physrd

Kevin Oberman oberman at
Fri Jul 16 16:15:57 PDT 2004

> Date: Fri, 16 Jul 2004 15:50:03 -0700
> From: Nate Lawson <nate at>
> Sender: owner-freebsd-current at

> While playing back a DVD on my Thinkpad, it hangs at some point (2-5
> minutes after beginning playback).  The player is hung in "physrd" and
> the drive stops spinning.  This hang happens when the drive is in PIO4
> or DMA mode.
> However, starting another process (i.e. cat /dev/acd0) spins up the
> drive and it works (and the other process begins running again).
> What's interesting is that I can quickly trigger this hang by starting
> IO on a completely different channel (i.e. dd if=/dev/ad0 of=/dev/null
> bs=1m).  This indicates that it may be a driver issue since the DVD
> drive that hangs is on a different channel and irq than the hard
> drive.
> Devices:
> atapci0: <Intel ICH3 UDMA100 controller> port
> 0x1860-0x186f,0x376,0x170-0x177,0x3f6,0x1f0-0x1f7 at device 31.1 on pci0
> ata0: at 0x1f0 irq 14 on atapci0
> ata1: at 0x170 irq 15 on atapci0
> [...]
> ad0: 19077MB <IC25N020ATMR04-0> [41344/15/63] at ata0-master UDMA100
> ata1-master: FAILURE - ATAPI_RESET no interrupt
> acd0: DVDROM <MATSHITADVD-ROM SR-8175> at ata1-master PIO4
> The same behavior also happens on my DVD/CDRW drive.
> ata1-slave: FAILURE - ATAPI_IDENTIFY no interrupt
> ata1-slave: FAILURE - ATAPI_IDENTIFY no interrupt
> ata1-master: FAILURE - ATAPI_RESET no interrupt
> acd0: CDRW <UJDA720 DVD/CDRW> at ata1-master PIO4

I have been seeing the same thing on my ThinkPad for a couple of
weeks. It may have been there for longer as I had not heavily used the
DVD for a while. There have been similar reports from others, but this
is the most exact match to what I have been seeing. Mine is a Toshiba
DVD/CDRW (DW-28E) at ata1-master UDMA33.
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at			Phone: +1 510 486-8634

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