[lug] DVD drive hanging system

[stimits at comcast.net]

One possibility to recover slightly more gracefully is via the magic sysrq keys. See:
https://en.wikipedia.org/wiki/Magic_SysRq_key
 
If enabled, you may be able to "alt-sysrq-s" to call sync, then "alt-sysrq-r" to force read-only remount. Then you are safe to explore or reboot or hard power down without further corruption. Reboot could be via "alt-sysrq-b". You may be able to use other sysrq magic keys to provide debugging information.
 
If you can log an OOPS someone might be able to debug it without the particular scratched DVD. It sounds like you have hit a bug in the driver. I can imagine that testing for this kind of corrupt data might be difficult...imagine if someone had to have the same DVD scratched in the same way to reproduce the problem. Although probably not too useful to you, you may be able to recover what is seen on the DVD via "dd". dd does not care about some of the drivers which would otherwise matter if you were reading it as a file system.
 

----- Original Message -----From: Jed S. Baer <blug at jbaer.cotse.net>To: LUG at lug.boulder.co.usSent: Sat, 13 Aug 2016 22:05:42 -0000 (UTC)Subject: [lug] DVD drive hanging system

Hi Folks.

Trying to figure out how to fix this - new drive?

If a DVD is particularly scratched up, my DVD drive will hang my system.Some things will still work, such as a text login on an alternateconsole, but even a shutdown gets only so far, and then hangs.

The DVD is ??? years old - nah, I don't know. It shares the SATAcontroller with /dev/sdc, i.e. it's /dev/sdd, so any operationsusing /dev/sdc will also hang. Swap is on /dev/sdc2 and /home ison /dev/sdc3, so it's pretty nasty when this happens.

The eject command doesn't eject, and the front panel eject button doesn'twork either. I've tried the pinhole "(*&%#)^&# eject" method, but itreally doesn't feel as if there's a button there.

Only way out of this is to power off. I've tried letting it sit for 10minutes, but it won't time out.

Some of these DVDs will play on the Blu-Ray player fine, others areclearly hosed.

So, what's the deal? If I can't interrupt the DVD drive, does it mean thedrive is bad? Most DVDs play just fine.

Is there magic incantation for 'really really really abort whatever'shappening with /dev/sr0 right now yes I do mean that'?_______________________________________________Web Page: http://lug.boulder.co.usMailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lugJoin us on IRC: irc.hackingsociety.org port=6667 channel=#hackingsociety
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lug.boulder.co.us/pipermail/lug/attachments/20160813/e266885b/attachment.html>