I had run X11 on this thinkpad X220 via the following command on tty1:

  exec startx 2>> ~/.xsession-errors

I recently suspended my machine; during this run, it had only been using LVDS.

I woke the machine back up, plugged in a DisplayPort connector, and
went to unlock xscreensaver.

I succesfully unlocked xscreensaver, and then X11 segfaulted.

here's the data from ~/.xsession-errors:
---------------------------
(EE)
(EE) Backtrace:
(EE) 0: /usr/bin/X (xorg_backtrace+0x56) [0x7f8a42933d46]
(EE) 1: /usr/bin/X (0x7f8a4277d000+0x1baf29) [0x7f8a42937f29]
(EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f8a40471000+0x35180) [0x7f8a404a6180]
(EE) 3: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f8a3c87a000+0x25bc5) [0x7f8a3c89fbc5]
(EE) 4: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f8a3c87a000+0xb972a) [0x7f8a3c93372a]
(EE) 5: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f8a3c87a000+0xc3f03) [0x7f8a3c93df03]
(EE) 6: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f8a3c87a000+0x50e03) [0x7f8a3c8cae03]
(EE) 7: /usr/bin/X (0x7f8a4277d000+0x13d3b1) [0x7f8a428ba3b1]
(EE) 8: /usr/bin/X (0x7f8a4277d000+0x133064) [0x7f8a428b0064]
(EE) 9: /usr/bin/X (0x7f8a4277d000+0x573f7) [0x7f8a427d43f7]
(EE) 10: /usr/bin/X (0x7f8a4277d000+0x5b596) [0x7f8a427d8596]
(EE) 11: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf5) [0x7f8a40492b45]
(EE) 12: /usr/bin/X (0x7f8a4277d000+0x4590e) [0x7f8a427c290e]
(EE)
(EE) Segmentation fault at address 0x18
(EE)
Fatal server error:
(EE) Caught signal 11 (Segmentation fault). Server aborting
----------------------------

This is an awkward thing to try to reproduce (i haven't tried in
depth, since i need to continue using the machine); if you have any
suggestions for additional data that would be useful, or ways i should
invoke X11 to help gather data, please let me know.

        -dkg

[266176.619] (EE) Backtrace:
[266176.621] (EE) 0: /usr/bin/X (xorg_backtrace+0x56) [0x7f08e0cbda36]
[266176.621] (EE) 1: /usr/bin/X (0x7f08e0b0b000+0x1b6c29) [0x7f08e0cc1c29]
[266176.621] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f08de7fc000+0x35180) [0x7f08de831180]
[266176.621] (EE) 3: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f08dabc0000+0x5e2aa) [0x7f08dac1e2aa]
[266176.621] (EE) 4: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f08dabc0000+0xded57) [0x7f08dac9ed57]
[266176.621] (EE) 5: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f08dabc0000+0x10ba30) [0x7f08daccba30]
[266176.621] (EE) 6: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f08dabc0000+0x10ce3c) [0x7f08daccce3c]
[266176.621] (EE) 7: /usr/lib/xorg/modules/drivers/intel_drv.so (0x7f08dabc0000+0x10d828) [0x7f08daccd828]
[266176.621] (EE) 8: /usr/bin/X (DRI2SwapBuffers+0x1d0) [0x7f08e0c905e0]
[266176.621] (EE) 9: /usr/bin/X (0x7f08e0b0b000+0x186f5c) [0x7f08e0c91f5c]
[266176.621] (EE) 10: /usr/bin/X (0x7f08e0b0b000+0x57f37) [0x7f08e0b62f37]
[266176.621] (EE) 11: /usr/bin/X (0x7f08e0b0b000+0x5c0bb) [0x7f08e0b670bb]
[266176.621] (EE) 12: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf5) [0x7f08de81db45]
[266176.621] (EE) 13: /usr/bin/X (0x7f08e0b0b000+0x464be) [0x7f08e0b514be]
[266176.621] (EE)
[266176.621] (EE) Segmentation fault at address 0x7f08e0f62000
[266176.621] (EE)
Fatal server error:
[266176.621] (EE) Caught signal 11 (Segmentation fault). Server aborting



Enrico

I can't see any similarities between your two traces, so please file
your own bug.

Thanks,
Julien

Cheers,
Tomasz