Linux power settings for NVME disk in Ubuntu 20.04.2 LTS

Asked by Piotr on 2021-06-09

Dear Launchpad Community,

I would like to ask you about one thing. I installed Ubuntu 20.04.2 LTS in my system where I have installed Kingston A2000 500 GB SSD. This is disk with NVME protocol. I readed on the internet that this disk have problem and this not working properly on linux family system. I contacted with device manufaturer and they said: " The flag nvme_core.default_ps_max_latency_us=5500 is a work around to address an issue discovered when the SSD goes into a low power state - until we can find a permament fix for it, we advidse applying this flag to your set up".

They also said that is no general issue with A2000 SSD when used with Linux because a small number of users have reported this issue.

I installed Ubuntu in my system and now I didn't noticed something strange in my system works but I want to have 100% sure that my disk work now fine. How I can check if my disk should have this flag? I must find some output to this issue in dmesg? How I can verify that I am affected with this issue and I must use above flag ? This is very important to me.

Please help.

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Piotr (peterq94) said (last edit ):
#1

I readed about this patch on kernel.org:

https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/log/

Mr Thorsten Leemhuis said: "you'll see a version that nearly identical to the one you mentioned; and if you search for A2000 in that repo you'll see that the patch was applied there:

https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=47add9f75714fabd3702dca0e5899a56d2f3ee2f"

I must know if it bug is fixed in kernel 5.8 for Ubuntu 20.04.2 --> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1916066

Should I install 5.4 kernel instead 5.8 if I use Kingston A2000?

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Manfred Hampl (m-hampl) said :
#2

What's the output of the commands

uname -a
cat /sys/module/nvme_core/parameters/default_ps_max_latency_us

as far as I can see from the source, kernel version linux-hwe-5.8_5.8.0-55.62~20.04.1 has already got the patch.
see yourself https://launchpad.net/ubuntu/+archive/primary/+sourcefiles/linux-hwe-5.8/5.8.0-55.62~20.04.1/linux-hwe-5.8_5.8.0-55.62~20.04.1.diff.gz

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Piotr (peterq94) said (last edit ):
#3

@Manfred Hampl. Why this website redirect me to https://launchpadlibrarian.net/541409572/linux-hwe-5.8_5.8.0-55.62~20.04.1.diff.gz

Is this legit website? I am little scary because this is uknown website for me. I found that Quttera said that this website is Malicious. I am safe or not now?

I have problem with Ubuntu 20.04.2 and I thinked that this can be problem with power settings. I have problem with sounds.

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Manfred Hampl (m-hampl) said :
#4

"Why this website redirect me to ...":
I gave that link, because on that page there is the proof that linux-hwe-5.8_5.8.0-55.62~20.04.1 has already got the patch to prevent deep powersave mode for A2000 NVME storage.

You have to accept that launchpad.net in some cases redirects to launchpadlibrarian.net
Just open http://launchpadlibrarian.net/ and see that this in turn refers back to launchpad.net

Only Quttera flags this file as potentially malicious, but this is definitely a false positive, because the page contains only plain text.
see https://www.virustotal.com/gui/url/f7caabd6ce0ca2c7b4b4363a9f6f46a4a7800665e01e202ed61c33d620187a4f/detection

If you have problems with sound, then this must have a different cause. The patch solves a problem that the NVME disk in some cases becomes fully unavailable after a certain time. It is only touching power settings for the NVME disk but nothing else.

Which version of the kernel are you running? Is it one that already includes the patch?

Revision history for this message
Piotr (peterq94) said :
#5

Yes, I use the newest 5.8 kernel for Ubuntu 20.04.1 so probably 5.8.0-55.62 like you mentioned.

I have only problem with the sound. Disk works fine.

Revision history for this message
Manfred Hampl (m-hampl) said :
#6

"I use the newest 5.8 kernel ..."
What the package management system takes as "newest" version of the kernels, is very much dependent on your configuration settings.

What is the output of the command
uname -a

If you have problems with sound and need help, then please follow the Ubuntu sound troubleshooting procedure.

Can you help with this problem?

Provide an answer of your own, or ask Piotr for more information if necessary.

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