Bug#801191: nvidia-driver: gdm3 can't start anymore (acceleration check failed)

[Andreas Beckmann]

On 2015-10-07 23:32, Manuel Bilderbeek wrote:
>> - and reload the module manually
>>      modprobe -r nvidia
> 
> This gave some errors....
> 
> rmmod: ERROR: Module nvidia_uvm is not currently loaded
> modprobe: FATAL: Error running remove command for nvidia_current

hmm, should have checked whether it is really unloaded

>>      modprobe nvidia
>>      ls -la /dev/nvidia*
>> - the nvidia devices should have 660 permissions now
> 
> They don't... still 666.
> 
>> - starting gdm should fail with the known error
>>      invoke-rc.d gdm3 start
> 
> That is indeed the case.

That's a bit confusing ... so let's test something more.

- can gdm3 be restarted?

    invoke-rc.d gdm3 stop
    invoke-rc.d gdm3 start

(if that already fails, skip the reminder)

- let's do the module dance again, this should be successful:

    invoke-rc.d gdm3 stop
    rmmod nvidia           # should give no error
    lsmod | grep nvidia    # should give no output
    modprobe -v nvidia-current
    ls -la /dev/nvidia*
    invoke-rc.d gdm3 start # expect: OK

- let's do the module dance again, and this I would expect to fail:

    invoke-rc.d gdm3 stop
    rmmod nvidia           # should give no error
    lsmod | grep nvidia    # should give no output
    modprobe -v nvidia
    ls -la /dev/nvidia*
    invoke-rc.d gdm3 start # expect: FAIL

if you could provide screenshots again, I could see the verbose output
from modprobe

>> The way the module gets loaded upon boot is somehow wrong since it is
>> ignoring the module options, so it works after reboot.
> 
> What is the difference between 'upon boot' and 'after reboot'?

Something seems to have recently changed what triggers the kernel module
to be loaded. Probably some hardware detection stuff, since the module
gets loaded under its renamed name "nvidia-current" without options,
while previously loading was triggered by X loading the nvidia_drv.so
module (which specifically requested the "nvidia" kernel module and that
gets loaded with some extra options).
I recently changed the modprobe-nvidia.conf to do the correct things
again and that seems to trigger these permission problems in gdm3, sddm, ...


Andreas