Question: I am using Ubuntu 20.04 on Dell vostro 7500. But the whole system crash frequently. The symptom is the screen shows no response to keyboard event and mouse event(mouse cannot move or click), but the screen is still light and showing the graphic contents(but everything including the time is stuck). `SysRq+REISUB`, which works in normal time on my machine, is invalid when crashing. And `/var/log/syslog` contains nothing after the crash. So it should be a ***kernel*** crash. Does anybody encounter this problem ever? I have reported this on launchpad <https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1909381>. Please vote on it if you also share the same problem.

After the crash, I updated my BIOS and fully tested my hardware and found no hardware error. Switching my kernel from `5.4.0-58-generic` back to `5.4.0-42-generic` also does not solve this problem.

I searched the contents in `syslog` just before the crash, but I found no much similar pattern. But the following line appears before both of the two crashes:

```
Dec 22 19:09:12 ofSimon kernel: [  878.796035] sof-audio-pci 0000:00:1f.3: error: no reply expected, received 0x0

```

I do not know what it means, and I noticed that this line also appear in `tty` every time when I shutdown my computer. Can anyone explain it to me?

Answer: 
I have upgrade the kernel from `5.4.0-58` to `5.8.0-36` for nearly 20 days and the crash has disappeared since then.
For those who share the same problem, you can upgrade your kernel from the official repository of ubuntu:

```
sudo apt install linux-image-5.8.0-36-generic

```

Best wishes.
sof-audio-pci errors are related to Sound Open Firmware. From their GIT page, "Sound Open Firmware is an open source community that provides an open source audio DSP firmware and SDK for audio or signal processing on modern DSPs." From what I understand, SOF, plus ALSA(Advanced Linux Sound Architecture), plus Pulse Audio all work together. It seems like there is a lot of activity around sound with newer hardware with people changing out kernels to support various features of their hardware.

From what I can tell, kernels later than 5.5.7 with the latest ALSA libs and latest Pulse Audio have this all worked out.

What I don't know is whether or not that error is causing our lockups. I have a brand new Lenovo X1 Yoga (Ubuntu 20.04) that is freezing up just like you describe. I too see the sof-audio-pci message just before one of the crashes. However, I can also use the computer for hours, check kern.log or dmesg and see the sof-audio-pci error messages without the computer locking up?