Linux 4.15 Is A Huge Update For Both AMD CPU & Radeon GPU Owners

[xpander]

I've been using disable c-state to prevent random reboot's on my Ryzen 7 1700, I presume we are all experiencing the same issue on Ryzen. It's not ideal long term if we are losing a low power saving mode however.

it still goes down to 0.9V and 1.9ghz (1.9ghz to 2.2 ghz in ondemand mode), so i dont think we loose much. C6 state is something else i guess, for boost state or similar

[LeJimster]

i was wondering why my screens went black, but the computer was on and couldnt connect to ssh either. that explains. i disablec C6 from bios, seems fine so far. i dont use those boost clocks anyway since i have OC on my cpu. This happened rarely though i even had 6 days uptime, but sometimes i got black screen right after 20 minutes of reboot or similar.

I've been using disable c-state to prevent random reboot's on my Ryzen 7 1700, I presume we are all experiencing the same issue on Ryzen. It's not ideal long term if we are losing a low power saving mode however.

[xpander]

i was wondering why my screens went black, but the computer was on and couldnt connect to ssh either. that explains. i disablec C6 from bios, seems fine so far. i dont use those boost clocks anyway since i have OC on my cpu. This happened rarely though i even had 6 days uptime, but sometimes i got black screen right after 20 minutes of reboot or similar.

[R41N3R]

I'm affected as well by random crashes, sometimes directly after boot. Thought it must be an issue with my AMD GPU, but didn't have the time to figure out what was going wrong. Good to know I'm not the only one! And hope this will be fixed soon, this bug is really bad for Ryzen and Linux.

[Mez']

Hence mainline kernel daily builds (.deb) now include it, right?

After installing it, it very well seems like it. Now waiting for rc1. Hopefully the suspend/resume issue will be solved by the last rc.

[Chewi]

Yes, as I said in the bug report, let's please stop with the stupid baseless FUD. I discovered the RCU_NOCB_CPU workaround myself after a lot of trial and error but didn't exactly shout about it from the rooftops so it's highly unlikely whoever removed the kernel option even knew about the issue.

[lucrus]

xiando wrote: He's actually a IBM asset,

Intel is the root cause of Ryzen hangs:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3fc5b3b6a80b2e08a0fec0056208c5dff757e547

https://bugzilla.kernel.org/show_bug.cgi?id=196683

I've read through all the kernel bug #196683 comments, and finally commenters think it's neither one (Intel/IBM), but they feel like it's a Ryzen CPU bug. However they're stuck at finding a way to contact the right AMD person to report the problem, and AMD hasn't commented on that bug as of today.

I do not own any Ryzen and I don't work for AMD, so there isn't much I can do to help here, except asking bridgman to have a look, maybe he knows how get in touch with the AMD CPU team.

[nanonyme]

Intel is the root cause of Ryzen hangs:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3fc5b3b6a80b2e08a0fec0056208c5dff757e547

https://bugzilla.kernel.org/show_bug.cgi?id=196683

Seth Jennings 2017-11-11 04:19:43 UTC
I found this commit that went into 4.12-rc2

Did anyone escalate the matter to Linus?

[theriddick]

Ryzen and R9 fury user here. waiting for it

The same here.

[xiando]

It crash on 4.13+ thanks to Intel

He's actually a IBM asset,

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/init/Kconfig?h=v4.14-rc3&id=44c65ff2e3b0b48250a970183ab53b0602c25764

https://paulmck.livejournal.com/47528.html

..and I do (ab)use rcu_nocbs=0-11 on my R5 1600X's. It took me a while to figure it out, I initially solved it by simply sticking with 4.12 after trying 4.13. This one is pretty serious, to me 4.12 to 4.13 was going from "works" to "hangs right after boot". It's a big deal, specially on headless boxes.

It's a total scandal, specially because nobody seems interested in fixing it which results in - as you helpfully point out - that a boot parameter is required for these CPUs to work properly. That's not exactly good. Nobody from AMD has commented or acknowledged this problem and I'm guessing they won't until some Ubuntu LTS release updates to a 4.13+ kernel.