Created attachment 1276371 [details]
Description of problem:
Boot fails with continuous flood of messages:
AMD-Vi: Completion-Wait loop timed out
VMD-Vi: Event logged [
after few minutes the kernel panics
Version-Release number of selected component (if applicable):
$ rpm -q kernel
Steps to Reproduce:
1. try to boot
Acer Aspire E-15 (E5-553G-F55F)
appending iommu=off results in successful boot.
This failure began with 4.9.4 kernel and a new firmware (sorry don't remember the version). Reverting to the older firmware fixed the problem for at least 4.9.4. 4.10.x fail the same way with either the old the most recent fw.
I've also tried ROCm kernel and the latest (1.5 4.9 based) fails the same way.
$ rpm -q linux-firmware
I can confirm that patch  from  applied on top of upstream 4.10.x fixes the issue for me.
Fedora 25 changed to end-of-life (EOL) status on 2017-12-12. Fedora 25 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.
If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
Thank you for reporting this bug and we are sorry it could not be fixed.