Hi,
I also added a quadro p400 in my Xpenolgy (3615xs and on a Hp microserver gen 8 ) and i'm interested of using it for Plex. After Doing some testing i was able to get at the same step as you, i get it to show my p400 with the command :
/usr/local/bin/nvidia-smi
but then it hangs forever and doesn't give me back the control... and if i start another ssh session and re-try /usr/local/bin/nvidia-smi.. it never does anything, just hang, only way to fix it is to restart. It does not crash the system at all, just create a dead process.
i do see the expected messages in dmesg
[ 359.424189] nvidia-nvlink: Nvlink Core is being initialized, major device number 247
[ 359.424506] nvidia 0000:07:00.0: enabling device (0040 -> 0043)
[ 359.424602] vgaarb: device changed decodes: PCI:0000:07:00.0,olddecodes=io+mem,decodes=none:owns=none
[ 359.424699] NVRM: loading NVIDIA UNIX x86_64 Kernel Module 381.22 Thu May 4 00:55:03 PDT 2017 (using threaded interrupts)
[ 371.699376] nvidia-modeset: Loading NVIDIA Kernel Mode Setting Driver for UNIX platforms 381.22 Thu May 4 00:21:48 PDT 2017
[ 379.116963] nvidia-uvm: Loaded the UVM driver in 8 mode, major device number 246
[ 415.006173] nvidia 0000:07:00.0: irq 62 for MSI/MSI-X
[ 415.455850] 32bit 0000:07:00.0 uses non-identity mapping
and i get this from the hanged command :
[ 601.188155] INFO: task nvidia-smi:24421 blocked for more than 120 seconds.
[ 601.188322] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 601.188505] nvidia-smi D ffff8801e7a92040 0 24421 20685 0x00000000
[ 601.188511] ffff88011bc7bbf0 0000000000000082 000000000000c000 ffff88011bc7bfd8
[ 601.188515] ffff88011bc7bfd8 ffff88008a5f5040 0000000000000000 ffffffffa16ae37a
[ 601.188518] ffff880003688008 7fffffffffffffff 7fffffffffffffff ffff88011bc7bd28
[ 601.188522] Call Trace:
[ 601.188730] [<ffffffffa16ae37a>] ? _nv012305rm+0x37a/0x400 [nvidia]
[ 601.188737] [<ffffffff814c0365>] ? schedule_timeout+0x155/0x1e0
[ 601.188896] [<ffffffffa18bed53>] ? _nv019507rm+0x23/0x70 [nvidia]
[ 601.189051] [<ffffffffa18beb07>] ? _nv019505rm+0x17/0x60 [nvidia]
[ 601.189217] [<ffffffffa18beb07>] ? _nv019505rm+0x17/0x60 [nvidia]
[ 601.189228] [<ffffffff814c1d60>] ? wait_for_completion+0x90/0xf0
[ 601.189232] [<ffffffff8105f110>] ? wake_up_state+0x10/0x10
[ 601.189237] [<ffffffff8104abf5>] ? flush_workqueue+0x115/0x5d0
[ 601.189334] [<ffffffffa13c29a2>] ? os_flush_work_queue+0x52/0x60 [nvidia]
[ 601.189468] [<ffffffffa198fab7>] ? rm_disable_adapter+0x77/0x130 [nvidia]
[ 601.189562] [<ffffffffa13b6837>] ? nv_close_device+0x77/0x170 [nvidia]
[ 601.189657] [<ffffffffa13ba8c7>] ? nvidia_close+0xd7/0x3a0 [nvidia]
[ 601.189754] [<ffffffffa13b6382>] ? nvidia_frontend_close+0x22/0x40 [nvidia]
[ 601.189759] [<ffffffff810fcf45>] ? __fput+0xc5/0x230
[ 601.189763] [<ffffffff810501ff>] ? task_work_run+0x8f/0xd0
[ 601.189767] [<ffffffff81002931>] ? do_notify_resume+0x61/0x80
[ 601.189771] [<ffffffff814c6067>] ? int_signal+0x12/0x17
I used these instructions/drivers to make it "works". As the more recent version of the driver given under or the one extracted from the pat of the DS1618+ (as suggested by King Butter) gives me the "Unknown symbol in module" when trying to inject into the kernel.
Trying on plex.. It's also detected but i get the same error :
[Transcode] [FFMPEG] - -> CUDA_ERROR_UNKNOWN: unknown error
I'm probably not helping you to make any progress, but i thought i would comment what i did in case it might help .
Thanks to everyone for the work trying to figure this out. If i can help in any way, let me know !