I agree this is not a driver issue.
After I change many BIOS setting and restore BIOS to default. Finally I reproduce the X1 Carbon 5th with PCIID 1577/1678/15d6.
Actually I don't know how exactly reproduce this issue, only 2 times reproduced.
When the failure happened the PCIID 1577/1578/15d6 shown that instead of 15d3.
And thunderbolt driver loaded with call trace, suspend will make system hang.
I agree this is not a driver issue.
After I change many BIOS setting and restore BIOS to default.
Finally I reproduce the X1 Carbon 5th with PCIID 1577/1678/15d6.
Actually I don't know how exactly reproduce this issue, only 2 times reproduced.
When the failure happened the PCIID 1577/1578/15d6 shown that instead of 15d3.
And thunderbolt driver loaded with call trace, suspend will make system hang.