Created attachment 133615 [details]
dmesg, showing a boot without iommu=soft

Hello amd devs,
and whomever it might affect or who is interested.


Kernel: 4.12.8
linux-firmware-amd-20170622
xf86-video-amdgpu-1.3.0
CPU: AMD A10-9600P
GPU: Radeon R7 (M440 or sth.)

After boot when presented with the login screen, the system repeatedly outputs "AMD-Vi: Completion-Wait loop timed out." and most of the time this corrupts the file system while doing this.
Booting the kernel with iommu=soft circumvents the problem, but introduces other issues on this machine.

I am following this issue for some time now.
A have a fairly recent notebook (yes, I know. it's a lot to ask for support on too recent hardware).
But i see hope, as there already has been succesfull patching by the amd crew!


I found a bugreport on launchpad [1] (strange enough they posted it there), which led to a patch on freedesktop [2], and i happily got it to work with 4.11. System was bootable without the iommu=soft command.

With linux now advancing to 4.12, the patch is not applyable anymore, so here i am now, reporting the issue again, in the hope to get new info and a tiny bit of help/advice.


Thanks in advance.


[1]: https://bugs.freedesktop.org/show_bug.cgi?id=101029
[2]: https://patchwork.freedesktop.org/series/21684/



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# lspci -vv | grep -A 3 -i "display"
03:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Topaz XT [Radeon R7 M260/M265 / M340/M360 / M440/M445] (rev ff) (prog-if ff)
	!!! Unknown header type 7f
	Kernel driver in use: amdgpu
	Kernel modules: amdgpu