Arch Linux

reverend

Member

Registered: 2016-10-29

Posts: 3

[SOLVED] Arch nvidia driver reporting monitor constantly reconnecting

I am running a fresh install of Arch linux (2016-10-01) and shortly after getting the basics set up, I noticed that my system would experience what seemed like microstutter. Anything moving on my screen (mouse cursor, loading icons, glxgears) would come to a complete halt for a split second every few seconds.

My first step was checking htop and I noticed that xorg-server was showing between 10-50% CPU usage. A cursory glance at Xorg.*.log (see below) showed that after what looks like a sane startup, my monitor is being polled/connected/reconnected/? multiple times per second. Many hours of googling did not seem to result in anything quite matching these symptoms. As much as I don't want to admit it, when it comes to drivers, I usually just install and forget, so please excuse my ignorance.

System Info

• GPU: PNY NVidia GTX 760

• Kernel: 4.8.4-1

• Driver: nvidia-370.28-2, nvidia-libgl-370.28-1

• Monitor: Changhong LED32YC1600UA (I don't trust any EDID information it might be providing and get-edid returned nothing. I imagine it could cause issues.)

Attempts to diagnose/fix

• Tried AUR nvidia-beta packages

• Tried switching to LTS kernel/driver

• Tried nomodeset

• Tried multiple users

• Tried multiple desktop environments (XFCE4, Gnome3)

• Tried multiple resolutions/refresh rates

• Tried various xorg.conf and xorg.conf.d/*.conf configurations:
  - setting MonitorConnected
  - setting IgnoreEDID

• EDIT: I did run mkinitcpio after any driver changes but my understanding is that it shouldn't matter if I can make it past the initramfs. Correct me if I'm wrong.

What I know

• Problem did not occur in Debian Jessie with nvidia.com binary driver.

• I have not had the chance to try a different monitor.

• I do not have data from the early part of the install before switching from nouveau to nvidia but the issue did not seem to be present previously.

• I have not tried installing drivers directly from nvidia.com and I'd like to avoid it if possible.

• The NVidia persistence daemon is running.

• Nouveau is apropriately blacklisted (does not appear in lsmod).

• Proper 1080p resolution not default on this monitor.

• Online documentation seems to suggest this monitors default refresh rate is 120 Hz but no operating system (linux/windows) has ever suggested this and often it's not even an option. Usually defaults to 59 Hz.

I would assume the log spam and the high cpu usage are related but if not, the high cpu/stuttering issue is my priority. I can work around the logs or find a fix later.

I hope all the information about the monitor is relevant.
Thanks

Xorg.0.log

perf top output snippet:

  41.10%  [nvidia]                            [k] _nv011765rm                  
   8.11%  [kernel]                            [k] acpi_idle_do_entry          
   2.77%  [nvidia]                            [k] _nv015267rm                  
   2.19%  [kernel]                            [k] read_tsc

Last edited by reverend (2016-10-30 10:29:36)

seth

Member

Registered: 2012-09-03

Posts: 51,312

Re: [SOLVED] Arch nvidia driver reporting monitor constantly reconnecting

"some" process frequently does the equivalent of "xrandr -q", the consequence is expectable.
Start a naked X server with an xterm and a WM like fvwm or maybe openbox. Ensure the problem isn't there as well.
Then you'll either have to determine the culprit by killing away everything until the problem is gone or wiresharking X11 - whatever feels easier to you ;-)

I'd start with the persistence daemon but Qt5 also *had* problems itr.

---

How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

reverend

Member

Registered: 2016-10-29

Posts: 3

Re: [SOLVED] Arch nvidia driver reporting monitor constantly reconnecting

Thanks seth. I'll give that a shot. I hadn't thought of running wireshark on X11. That's a cool idea.

reverend

Member

Registered: 2016-10-29

Posts: 3

Re: [SOLVED] Arch nvidia driver reporting monitor constantly reconnecting

Sorry for not getting back sooner. I haven't had much time to play with this.

I managed to get the xserver to listen to tcp connections so I could check the traffic with wireshark and I'm not entirely sure what I saw. There were a ton of packets containing piles of opcodes being sent to port 6000 from a single port. I used lsof to determine that the port belonged to Xorg and, after a little snooping, I determined that the opcodes being sent (almost all were 138 and 143) were GLX related. For all I know, this is normal though.

I can confirm two new things since the last time I posted. One is that the problem still persists using openbox and the other is that it does not happen when using nouveau.

I'm not really sure where to go from here.

EDIT
For the sake of being thorough, I tried a different monitor (a real computer monitor as opposed to a no-name brand TV) and the problem is gone! Unless anyone has anything more to add, I'm going to mark this as solved because I think at this point, it's safe to chalk it up to bad/low-quality hardware. Thanks again for the help.

Last edited by reverend (2016-10-30 10:27:02)