After several weekends of testing, I believe I can report with high confidence that the kernel update to 4.17-rc2 fixes the second of the two problems; specifically, we no longer see kernel crashes after using Alt-SysRq-k to recover from frozen/hanging blank screens.
However, the unable-to-unblank problem remains; after normal screen blanking, about 50% of the time we are unable to recover by moving the cursor or typing a key. Instead, only Alt-SysRq-k allows us to recover back to a guest login screen. There doesn't seem to be much in the system logs that I can find, except possibly this: May 20 20:41:04 Comprm8 gnome-session[7919]: gnome-session-binary[7919]: GLib-GIO-CRITICAL: g_dbus_connection_call_internal: assertion 'object_path != NULL && g_variant_is_object_path (object_path)' failed May 20 20:41:04 Comprm8 gnome-session-binary[7919]: GLib-GIO-CRITICAL: g_dbus_connection_call_internal: assertion 'object_path != NULL && g_variant_is_object_path (object_path)' failed Some seemingly similar bug reports from out in the wild: https://askubuntu.com/questions/795014/ubuntu-16-04-occasionally-hangs-with-screen-off-after-switching-ttys-or-turning https://askubuntu.com/questions/949764/ubuntu-hangs-when-unlocking-screen Can you recommend any approaches to help debug the root cause of this problem, presumably in X and/or the radeon driver? -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1763273 Title: kernel panic in Radeon driver while screen blank To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1763273/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp
