OK ... I think that's all I can do for today.  I've uploaded as
attachments to this original report all the files generated by apport-
bug today, and marked the other ticket as a duplicate.

(I apologize for that, but I can't use my personal Launchpad account
from the kiosks, and I'm only there once a week, so I used the "RBL
Admin" account to generate the requested apport-bug files.  I've marked
the extra ticket as a duplicate of this one now that I've copied over
all the files.)

As I noted earlier when I had direct access to the machines, this seems
to be a pair of issues, both possibly in the Radeon driver.  The "unable
to unblank after idle" problem is shown in the Xorg.0.log file from
today, and also in the XorgLogOld.txt file from apport-bug -- namely,
Xorg errors reporting keyboard and mouse events are being dropped.

And, when we do a "hard resume" by issuing Alt-SysRq-k, that sometimes
works to get back to the login screen, and sometimes generates a kernel
crash in the radeon driver -- as shown in the apr1.full.kern.log (all
the /var/log/kern.log* entries from April 1st) and the accompanying
kernel stacktrace photo in radeon_kernel_panic1.jpg.

Please let me know if there's any further data I can try to collect next
week when I'm on-site again.  Thanks very much,


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  kernel panic in Radeon driver while screen blank

Status in linux package in Ubuntu:
Status in xorg package in Ubuntu:

Bug description:
  I maintain a set of older kiosks running a mix of stock Ubuntu 14.04
  LTS and 16.04.  As we have gradually transitioned them to 16.04, we
  have noticed that the machines running 16.04.1 now regularly exhibit
  problems restoring from the blank screen which appears after a period
  of inactivity.

  This only occurs on the machines where we've installed 16.04.  All of
  the 16.04.1 installations are "fresh", that is, complete re-installs
  from scratch, and we install all security and other updates on a
  regular basis.  This problem has persisted right from the beginning
  when we started using 16.04.

  Following a period of user inactivity, the screen goes blank; this is,
  of course, expected.  When the user tries to restore the session by
  typing a key or moving the mouse, one of three outcomes occurs.

  Sometimes, the session restores normally.  Other times, the screen
  remains blank regardless of all normal keyboard input, until a magic
  SysRq  sequence is performed.  After Alt-SysRq-k, either the virtual
  console resets to a login screen (as expected after this SysRq
  sequence), or we get a kernel panic text screen (see attached screen
  photo) and can only restore via a hard power-cycle reboot.

  I will continue to try to capture a better trace output from one of
  these conditions, perhaps from /var/log/kern.log or by installing
  linux-crashdump (although these old machines may not have enough
  memory for the stock package).  But in the meantime, I'm attaching a
  photo of the kernel panic we see, which suggests a problem may reside
  in the Radeon driver ... which would seem possible, given the general
  blank-screen no-resume problem on these systems.

  Any advice on how to further capture any other needed details would be
  appreciated.  Thanks very much!

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