Open Radar

 
Area:
Graphics & Imaging

Summary:

When disconnecting eGPU using "disconnect eGPU" option from menubar, loginwindow occasionally appears to crash and log user out.

Steps to Reproduce:

BACKGROUND

Machine is a 2018 15" MacBook Pro, Vega 20 internal graphics, eGPU is a Radeon Vega 64 Frontier Edition in Sonnet 650 case. Use case is mobile / office environment where MacBook Pro transitions between laptop and office "clamshell" mode connected to an eGPU with then two external monitors are plugged into eGPU. ie MacBook Pro -> eGPU -> external monitors.

I am unable to find documentation as to the appropriate way to transition between "laptop" mode and "clamshell eGPU" mode. This is the procedure I use that appears to work most of the time.

Laptop -> desktop mode...

1. Ensure MacBook Pro is awake and user is log in
2. Plug in eGPU, wait for both external monitors to display desktop
3. Close laptop to enter into "clamshell mode"

Desktop mode -> laptop mode

1. Ensure MacBook is awake and user is logged in
2. Close all applications that are using external graphics
3. Open MacBook Pro lid, wait until desktop is visible on-screen (disabled)
4. Select "disconnect eGPU" from menu bar (menubar is only active on external monitors)
5. Wait until desktop disappears from external monitors and laptop desktop is active.
6. Unplug eGPU

Expected Results:

System transitions between laptop mode and desktop mode and vice versa without incident

Actual Results:

Occasionally, and seemingly without rhyme or reason, the login window appears to crash logging out the user. I am aware that this may happen if the eGPU is disconnected without first manually disconnecting it from the menubar but this is NOT the case here.

I've attached syslog output of the most recent crash at the end.

Couple of lines catch my eye:

Line 6 states "VDCAssistant[183]: BUG in libdispatch client"

Line 9 states "(com.apple.WindowServer[142]): Service exited due to SIGSEGV "

Version/Build:

10.14.2 (18C54)