[SOLVED]kernel regression with 4.13.3 and newer

Inxsible · 2017-10-11 03:35:42

Recently, I had the issue of my display not showing me anything when I updated my machine. I went through my recently upgraded packages and downgraded linux to 4.12.13-1 and everything started working. I assumed it might be a minor bug which would be fixed in the next release and just used the last working version since I didn't have time to investigate. After upgrading to 4.13.4-1, I stil had the issue. So I found this thread which resolved the issue for me.

I now have the latest linux kernel working.

What I don't understand is that why does enabling/disabling the Intel Input Output Memory Management Unit have anything to do with my display not working. And what bugfix/feature/regression in the linux kernel brought this to the fore?

Searching for that doesn't lead to specifics that I am looking for. Some insight on this would be helpful.

Thank you,

Last edited by Inxsible (2017-10-13 15:39:23)

Scimmia · 2017-10-11 03:53:24

IOMMU is a layer between devices and the main memory. It can affect all kinds of things, including graphics. See https://en.wikipedia.org/wiki/Input%E2% … ement_unit

As for what changed, it was enabled by default in Arch's stock kernel. That's been reverted for 4.13.5

Inxsible · 2017-10-11 04:33:39

Scimmia wrote:

As for what changed, it was enabled by default in Arch's stock kernel. That's been reverted for 4.13.5

Hmmm... So it was disabled by default until 4.12.13-1, then enabled by default for 4.13.3-1 & 4.13.4-1 and now being disabled by default again for 4.13.5 ?

The mirrors I use still have 4.13.4-1 on them, so I guess once I update to 4.13.5, I might be able to remove the kernel parameter intel_iommu=off

Last edited by Inxsible (2017-10-11 04:34:34)

Scimmia · 2017-10-11 05:22:16

4.13.5 is currently in testing, but yes, once you upgrade, intel_iommu=off will be the default again and you won't have to specify it anymore.

Inxsible · 2017-10-13 15:38:59

Thanks.

I updated to 4.13.5 and was able to boot without the kernel parameter.

Arch Linux

#1 2017-10-11 03:35:42

[SOLVED]kernel regression with 4.13.3 and newer

#2 2017-10-11 03:53:24

Re: [SOLVED]kernel regression with 4.13.3 and newer

#3 2017-10-11 04:33:39

Re: [SOLVED]kernel regression with 4.13.3 and newer

#4 2017-10-11 05:22:16

Re: [SOLVED]kernel regression with 4.13.3 and newer

#5 2017-10-13 15:38:59

Re: [SOLVED]kernel regression with 4.13.3 and newer

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