I had this problem when i installed Ubuntu 20.04, i manage to solve it by installing Ubuntu again , and installing old drivers. Now a couple months later, i suspend my computer and get a black screen after i come back.
uname -a
Linux noblepc 5.8.0-55-generic #62~20.04.1-Ubuntu SMP Wed Jun 2 08:55:04 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Nvidia Driver - 460.80 Cant install old drivers , without them getting updated automatically!
GPU - GTX 1050
What is strange is that i had this problem solved , and for no reason it came back, and now i cant manage to solve the problem , even after a bunch of solutions.
Error
Nvidia-Modeset: Failed to allocate display engine core DMA push buffer!
Nvidia-Modeset: GPU 0: Display engine push buffer channel allocation failed 0x65
Edit:
I Managed to solve this problem installing Driver-server