https://bugs.freedesktop.org/show_bug.cgi?id=108585
--- Comment #6 from Benjamin Herrenschmidt benh@kernel.crashing.org --- They may or may not be related ... Alex, kexec is how we boot these machines, there's a Linux kernel in flash that runs a Linux based bootloader.
Until recently however, that didn't have an amdgpu driver. This might have changed.
Dan... did you do some firmware changes here ? Could it have to do with the versions differences between petitboot and the final kernel ?
Alex, whether we track it here or separately, we probably need to look into kexec support. It's not just us, there's a bit of momentum around kexec based bootloaders (google's on it too) as was seen at the recent OSFC (firmware conf).
A workaround in the meantime (for kexec problems) could be to hot reset the card during the transition I suppose.