Nvidia Card doesn't register udev hotplug event

GPU Unix Graphics Linux
#1

I’ve looked through tons of posts, I can’t seem to get a udev rule to trigger when unplugging an HDMI or DP. Nothing shows in:

udevadm monitor --property

Also I made a rules file in udev and it doesn’t trigger the script I have tied to it:

99-monitor-hotplug.rules

ACTION==“change”, SUBSYSTEM==“drm”, ENV{HOTPLUG}==“1”, RUN+="/usr/local/bin/monitor-hotplug.sh"

OS: Ubuntu 16.04.04 LTS
Video Card: Nvidia GTX 1080

Any thoughts on how to get this to trigger?

#2

You would have to use either the kernel parameter
nvidia-drm.modeset=1
or have a file in /etc/modprobe.d containing

options nvidia-drm modeset=1

to get the drm sysfs nodes.
sudo cat /sys/module/nvidia_drm/parameters/modeset
should return ‘Y’ if done right.

But I don’t think that will work since the drm monitor stuff in the nvidia driver still isn’t wired up completely. Please check and report back.

#3

Hi generix,

Thanks for your response. I tried:

sudo modprobe -r nvidia-drm
sudo modprobe nvidia-drm modeset=1

then rebooted:

returned N for sudo cat /sys/module/nvidia_drm/parameters/modeset

Then I made an entry in a new file nvidia.conf in /etc/modprobe.d/:

options nvidia-drm modeset=1

and ran: sudo update-initramfs -u

returned N for sudo cat /sys/module/nvidia_drm/parameters/modeset

Then I also found in a post that said grub.cfg should be updated so I edited /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT=“quiet splash i915.modset=1 log_buf_len=1M nvidia-drm.modeset=1”

sudo update-grub

return N for sudo cat /sys/module/nvidia_drm/parameters/modeset

Do you have any other suggestions possible? Thanks for your help so far

#4

I missed that you’re on 16.04, there the nvidia modules are renamed.
modify the file in /etc/modprobe.d to read

options nvidia_XXX_drm modeset=1

with XXX being the major version of the nvidia drivers installed and run sudo update-initramfs -u and reboot.

#5

Hi Generix,

Your solution got me the udev rule hotplug event!

I now get this output:

UDEV [52.870606] change /devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0 (drm)
ACTION=change
DEVNAME=/dev/dri/card0
DEVPATH=/devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0
DEVTYPE=drm_minor
HOTPLUG=1
ID_FOR_SEAT=drm-pci-0000_01_00_0
ID_PATH=pci-0000:01:00.0
ID_PATH_TAG=pci-0000_01_00_0
MAJOR=226
MINOR=0
SEQNUM=3528
SUBSYSTEM=drm
TAGS=:seat:master-of-seat:uaccess:
USEC_INITIALIZED=2413437

UDEV [53.085358] change /devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0 (drm)
ACTION=change
DEVNAME=/dev/dri/card0
DEVPATH=/devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0
DEVTYPE=drm_minor
HOTPLUG=1
ID_FOR_SEAT=drm-pci-0000_01_00_0
ID_PATH=pci-0000:01:00.0
ID_PATH_TAG=pci-0000_01_00_0
MAJOR=226
MINOR=0
SEQNUM=3529
SUBSYSTEM=drm
TAGS=:seat:master-of-seat:uaccess:
USEC_INITIALIZED=2413437

for some reason it doesn’t seem to trigger a response in my 99-monitor-hotplug.sh file /etc/udev/rules.d/:

SUBSYSTEM==“drm”, ACTION==“change”, ENV{HOTPLUG}==“1”, RUN+="/usr/local/bin/hotplug.sh"

Is there something specific I need to do in this file that I haven’t?

Thanks

#6

Depends on what you’re doing in that script. To debug, e.g. add
date >> /var/log/drmhotplug.log
to that script. Use udevadm test to see if the rule is properly triggered.

#7

Hi Generix,

I get this back on trying udevadm test:

calling: test
version 229
syspath parameter missing

Doesn’t seem to be properly triggered, drmhotplug.log doesn’t show up in /var/log/

I can’t seem to find find any info on syspath, could you please assist?

Thanks

#8

That was merely a hint, not a full cmdline.
udevadm test --action=change /devices/pci0000:00/0000:00:01.0/0000:01:00.0/drm/card0
though that doesn’t set the HOTPLUG env

#9

Hi Generix,

I was able to get the udev event to trigger based on your advice. For some reason I cannot seem to load an OpenCV based program in the script. When I run the script by itself it loads the OpenCV based program fine. Do you have any thoughts on this?

Thanks

#10

If it’s a GUI application, you’ll have to set the DISPLAY and XAUTHORITY variable. Probably also the user so it doesn’t get run as root.

#11

Hi Generix,

I have set these environment variables in my script before the GUI application:

export XAUTHORITY=/home//.Xauthority
export DISPLAY=:0.0

The GUI application still doesn’t seem to load via the Udev rule. I am not sure how to set the user, is it su - username -C ?

Thanks

#12

So I am running with in my 99-monitor-hotplug.sh:

SUBSYSTEM==“drm”, ACTION==“change”, ENV{HOTPLUG}==“1”, RUN+="/bin/sh -c ‘DISPLAY=:0 XAUTHORITY=/home//.Xauthority /home//Downloads/hotplug.sh’"

Works fine from command line and launches the script and the GUI application runs. I do not see the GUI application run when the udev event is triggered, but I know it is triggered because a file I am writing to in hotplug.sh shows up in /var/log/ .

Any ideas on how to fix?

Thanks

#13

Don’t really know.
Are you sure the DISPLAY and XAUTHORITY variables are set to the correct values?
Please post the output of
ps aux |grep X

#14

Hi Generix,

Here is the output of ps aux | grep X :

ps aux |grep X
root 1118 4.7 0.6 407492 98936 tty7 Ssl+ 11:37 0:03 /usr/lib/xorg/Xorg -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
hom+ 2595 0.0 0.0 21292 1080 pts/1 S+ 11:39 0:00 grep --color=auto X

Thanks

#15

Try
XAUTHORITY=/var/run/lightdm/root/:0

#16

Hi Generix,

This is my new 99-monitor-hotplug.sh:

SUBSYSTEM==“drm”, ACTION==“change”, ENV{HOTPLUG}==“1”, RUN+="/bin/sh -c ‘DISPLAY=:0 XAUTHORITY=/var/run/lightdm/root/:0 /home//Downloads/hotplug.sh’"

The udev rule triggers but still does not start my GUI application.

Thanks for your help so far

#17

Since /home//Downloads/hotplug.sh is being run if I understand correctly, start the application in it like
application 2>&1 >>/var/log/application.log
to see what error gets thrown, if any.

#18

Hi Generix,

The file appears empty for application.log . This is an OpenCV based program, does this mean the program is actually launching?

Thanks

#19

I’m sorry, wrong order. Try
application >/var/log/application.log 2>&1

#20

Hi Generix,

It says:

/home//Downloads/hotplug.sh: 13: /home//Downloads/hotplug.sh: ./opencvapp: not found

I don’t see how this is possible, I cd into the folder where the opencvapp is earlier in hotplug.sh. Also when I run hotplug.sh it loads opencvapp fine. Any ideas?

Thanks