I am using integrated graphics on an AMD 5700G processor. I am using the xfce desktop environment.
My original bug report document the result of console switching, but noted that the same problem occurred when unlocking a session. I have subsequently verified that when a session is locked by Light Locker, when the user attempts to unlock the session the user is logged out and the x-0.log.old contains a stack backtrace which is identical (except for the addresses in square brackets) to the stack trace included in my original bug report. I disabled session locking, and confirmed that this makes the problem go away. Specifically, if the session is left idle long enough for the screen to power down, the X server can unblank the screen without crashing. I switched from the testing distribution to the bullseye distribution, and the problem went away, indicating that this problem is a regression.
