Status changed to 'Confirmed' because the bug affects multiple users.
** Changed in: xorg (Ubuntu)
Status: New => Confirmed
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kernel panic in Radeon driver while screen blank
Status in linux package in Ubuntu:
Status in xorg package in Ubuntu:
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
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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