I've been burning DVD's (data backups) for a few days here, using k3b. I always select the option to verify the data to be sure the burn went correctly. For the first several DVD's, whenever a burn would finish, the CD would eject, then it would be reloaded for the verify. When the disc was reloaded, KDE would notice and pop a window, asking me what I wanted to do (mount the disc or ignore it). This was bothersome, but not disruptive, because the disc would not be mounted, because I wouldn't respond. Thus, when the verify finished, the disc would again be ejected.
There has been a mysterious change in behavior. I haven't rebooted or anything. It just changed. Now, when the burn is finished, the disc is ejected, and then reloaded automatically for the verify. But now, the dialog that would ask me what to do with the disc doesn't appear, and when the verify is finished, the disc does not automatically eject. The disc does not show up under media:/, so it's not mounted, but that also means that the only way I can eject it is from a terminal shell (the button doesn't work). When I do eject the disc this way and reload it, KDE does not pop up a window, asking me what to do. I also cannot eject it with the button, and it does not show up under media:/. This is the case for any disc (CD or DVD) I put in the drive.
At no point did I intentionally or accidentally indicate a default behavior for when a disc is inserted. It seems that some part of KDE has started malfunctioning, but I did not get any kind of error message about a process crashing. I don't intend to reboot this machine for a while, so if there is something you would like me to do to investigate this, please let me know.
Here's some info from dmesg that appears when I insert a DVD:
[162454.021442] warning: many lost ticks.
[162454.021445] Your time source seems to be instable or some driver is hogging interupts
[162454.021459] rip __do_softirq+
[193482.094098] cdrom: This disc doesn't have any tracks I recognize!
[193848.083009] Assertion failed! qc->n_elem > 0,drivers/
[193848.103395] Assertion failed! qc->n_elem > 0,drivers/
[193848.154100] Assertion failed! qc->n_elem > 0,drivers/
[193848.166449] Assertion failed! qc->n_elem > 0,drivers/
[193848.600024] Assertion failed! qc->n_elem > 0,drivers/
[193848.612466] Assertion failed! qc->n_elem > 0,drivers/
[193946.140904] Assertion failed! qc->n_elem > 0,drivers/
[195027.545489] Assertion failed! qc->n_elem > 0,drivers/
[195027.575962] Assertion failed! qc->n_elem > 0,drivers/
[195027.579736] Assertion failed! qc->n_elem > 0,drivers/
[195027.666187] Assertion failed! qc->n_elem > 0,drivers/
[195095.223095] cdrom: This disc doesn't have any tracks I recognize!
[195268.832957] Assertion failed! qc->n_elem > 0,drivers/
[195268.848535] Assertion failed! qc->n_elem > 0,drivers/
[195268.896228] Assertion failed! qc->n_elem > 0,drivers/
[195268.908140] Assertion failed! qc->n_elem > 0,drivers/
[195269.076103] Assertion failed! qc->n_elem > 0,drivers/
[195269.087963] Assertion failed! qc->n_elem > 0,drivers/
[195346.918087] cdrom: This disc doesn't have any tracks I recognize!
[196022.415894] Assertion failed! qc->n_elem > 0,drivers/
[196022.447887] Assertion failed! qc->n_elem > 0,drivers/
[196022.496535] Assertion failed! qc->n_elem > 0,drivers/
[196022.526594] Assertion failed! qc->n_elem > 0,drivers/
[196022.658486] Assertion failed! qc->n_elem > 0,drivers/
[196022.688563] Assertion failed! qc->n_elem > 0,drivers/
[196836.232856] cdrom: This disc doesn't have any tracks I recognize!
[196836.337846] cdrom: This disc doesn't have any tracks I recognize!
[196905.896438] Assertion failed! qc->n_elem > 0,drivers/
[197468.430274] Assertion failed! qc->n_elem > 0,drivers/
[197468.442986] Assertion failed! qc->n_elem > 0,drivers/
[197468.445037] Assertion failed! qc->n_elem > 0,drivers/