Bug#944874: strange phenomenon with primus + nvidia-tesla

[Patrice Duroux]

Andreas,

Many thanks for your attention!
Each boot I am observing this:

[   11.601498] bbswitch: loading out-of-tree module taints kernel.
[   11.601540] bbswitch: module verification failed: signature and/or required key missing - tainting kernel
[   11.601693] bbswitch: version 0.8
[   11.601697] bbswitch: Found integrated VGA device 0000:00:02.0: \_SB_.PCI0.GFX0
[   11.601702] bbswitch: Found discrete VGA device 0000:01:00.0: \_SB_.PCI0.PEGP.DGFX
[   11.601714] ACPI Warning: \_SB.PCI0.PEGP.DGFX._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20190703/nsarguments-59)
[   11.602324] bbswitch: detected an Optimus _DSM function
[   11.602339] pci 0000:01:00.0: enabling device (0000 -> 0003)
[   11.602402] bbswitch: Succesfully loaded. Discrete card 0000:01:00.0 is on
[   11.602900] bbswitch: disabling discrete graphics

(bbswitch is well activated keeping NVIDIA driver silent)

but then sometimes still during the boot and I don't known the reason for,
the driver tries to be loaded but without success (because by-passing bbswitch):

[   11.696440] nvidia: module license 'NVIDIA' taints kernel.
[   11.696442] Disabling lock debugging due to kernel taint
[   11.718958] nvidia-nvlink: Nvlink Core is being initialized, major device
number 241
[   12.030091] nvidia 0000:01:00.0: enabling device (0000 -> 0003)
[   12.030208] nvidia 0000:01:00.0: vgaarb: changed VGA decodes:
olddecodes=io+mem,decodes=none:owns=none
[   12.030238] NVRM: The NVIDIA GPU 0000:01:00.0
               NVRM: (PCI ID: 10de:12b9) installed in this system has
               NVRM: fallen off the bus and is not responding to commands.
[   12.030296] nvidia: probe of 0000:01:00.0 failed with error -1
[   12.030329] NVRM: The NVIDIA probe routine failed for 1 device(s).
[   12.030329] NVRM: None of the NVIDIA graphics adapters were initialized!
[   12.066156] nvidia-nvlink: Unregistered the Nvlink Core, major device number
241

This happens many times in the same boot process.

Can this wake-up may be due to HDMI HDA audio driver?
Because I can this such messages:

[   14.030141] snd_hda_codec_hdmi hdaudioC1D0: Unable to sync register 0x4f0800.
-5
[   14.030148] snd_hda_codec_hdmi hdaudioC1D0: HDMI: invalid ELD buf size -1
[   14.030152] snd_hda_codec_hdmi hdaudioC1D0: HDMI: invalid ELD buf size -1
...

Then most of the time, optirun is not able to work at all.
Is the NVIDIA driver after such boot case in a state that bbswitch cannot
operate with correctly.
Sorry don't know how to help more!...

Patrice