A week ago, I updated Ubuntu on my ASUS X556U laptop from 18.04 to 19.10. (I did it in two steps: 18.04 to 19.04 and immediately 19.04 to 19.10) After this update I got a strange problem. My laptop cannot resume from suspend every third suspend/resume cycle. It is dead after the third suspend. No disk activity. Two suspend/resume cycles are good, the third fails. I am sure the problem is in nouveau and my NVIDIA GeForce 940MX card. I get the following error messages all the time:
**nouveau 0000:01:00.0: bus: MMIO read of 00000000 FAULT at 6013d4 [ IBUS ]**
Prior to version 18.04, I could not turn off my laptop if I suspended and resumed it earlier, because NVIDIA didn't stop. But, after the update to 18.04, I had no visible problems with nouveau.
I don't see anything suspicious in logs, although I do not have much experience in analyzing logs.
Is there any idea what is going on? Is there anything I can do?