ACPI Error: Method parse/execution failed; NVRM: Xid: 79, GPU has fallen off the bus

I've got two problems:

1. My laptop does not wake up when it is suspended and it shows these messages in a black screen:

   [349.417870] ACPI Error: [\_SB_.PCI0.LPCB.H_EC.ECWT] Namespace
   lookup failure, AE_NOT_FOUND (20170531/psargs-364)             
   [349.417881] ACPI Error: Method parse/execution failed \_TZ.FN04._OFF,         AE_NOT_FOUND (20170531/psparse-550)   
   [349.417963] ACPI Error: [\_SB_.PCI0.LPCB.H_EC.ECWT] Namespace
   lookup failure, AE_NOT_FOUND (20170531/psargs-364)             
   [349.417970] ACPI Error: Method parse/execution failed \_TZ.FN03._OFF,         AE_NOT_FOUND (20170531/psparse-550)  
   [349.418041] ACPI Error: [\_SB_.PCI0.LPCB.H_EC.ECWT] Namespace
   lookup failure, AE_NOT_FOUND (20170531/psargs-364)             
   [349.418047] ACPI Error: Method parse/execution failed \_TZ.FN02._OFF,        AE_NOT_FOUND (20170531/psparse-550)   
   [349.418114] ACPI Error: [\_SB_.PCI0.LPCB.H_EC.ECWT] Namespace
   lookup failure, AE_NOT_FOUND (20170531/psargs-364)             
   [349.418121] ACPI Error: Method parse/execution failed \_TZ.FN01._OFF,         AE_NOT_FOUND (20170531/psparse-550)   
   [350.802831] ACPI Error: [\_SB_.PCI0.LPCB.H_EC.ECWT] Namespace
   lookup failure, AE_NOT_FOUND (20170531/psargs-364)                   
   [350.802934] ACPI Error: Method parse/execution failed \_TZ.FN00._OFF,        AE_NOT_FOUND (20170531/psparse-550) 
   [350.925661] ACPI Error: [\_SB_.PCI0.PEG0.OFSV] Namespace lookup failure, AE_NOT_FOUND (20170531/psparse-550)  
   [350.925780] ACPI Error: Method parse/execution failed \S_B.PCI0.PGOF, AE_NOT_FOUND (20170531/psparse-550)   
   [350.925880] ACPI Error: Method parse/execution failed \S_B.PCI0.PEG0.PG00._OFF, AE_NOT_FOUND (20170531/psparse-550)  
   [350.928692] NVRM: Xid (PCI:000:04:00): 79, GPU has fallen off the bus.
   

2. I've tried to disable the suspend mode when I close the lid, modifying the /etc/systemd/logind.conf file and the /etc/UPower/UPower.conf file but none of those worked.

What should I do?

As per Xid errors list, error 79 (GPU has fallen off the bus) can be related to variety of things such as driver or hardware issue, system memory corruption, bus error or thermal issue (overheating).

Run NVIDIA X Server Settings app (which comes with the drivers) and check the temperature, graphic clock, performance levels and GPU utilization levels.

The following post (based on this original thread), suggests to disable PCI-E ASPM (Active State Power Management) by changing boot params to pcie_aspm=off (it forcibly disables PCIe ASPM).

Related bug report: GPU has fallen off the bus.