Bug 1464204 - Displays fail to wake up when booting machine away from Display Port KVM switch
Displays fail to wake up when booting machine away from Display Port KVM switch
Status: NEW
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: xorg-x11-drv-nouveau (Show other bugs)
x86_64 Linux
unspecified Severity high
: rc
: ---
Assigned To: Ben Skeggs
Desktop QE
Depends On:
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Reported: 2017-06-22 12:08 EDT by Dhruv Thakkar
Modified: 2018-03-15 01:33 EDT (History)
0 users

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Attachments (Terms of Use)
Xorg.0.log (45.25 KB, text/plain)
2017-06-22 12:08 EDT, Dhruv Thakkar
no flags Details
/var/log/messages (2.40 MB, text/plain)
2017-06-22 12:09 EDT, Dhruv Thakkar
no flags Details
xorg.conf for nouveau drivers (2.97 KB, text/plain)
2017-06-22 12:10 EDT, Dhruv Thakkar
no flags Details

  None (edit)
Description Dhruv Thakkar 2017-06-22 12:08:20 EDT
Created attachment 1290764 [details]

Description of problem:

We are trying to solve an issue in which displays fail to wake up when booting a Rhel 7.3 machine (Machine A) connected to a Display Port KVM while the KVM is pointing to Machine B. The unusual bit is that xorg logs in /var/log/Xorg.0.log indicate that everything comes up correctly, and a "ps -ef |grep X|xinit" shows that X and xinit are up and running. If we boot Machine A while the KVM is pointing to it, the displays come up with no issues.

We have KMS parameters set to force the output of the video (video=DP-1:2560x1600D and video=DP-2:2560x1600D) as well as options to load the EDID information. These parameters have worked in the past for us when we used DVI connections through KVMs, but DisplayPort is not showing the same results. Note that we have additional kernel options added for extra debug information (log_buf_len=8M nouveau.debug=disp=trace,i2c=trace,bios=trace)

Using Xrandr and Udev rules with a script allow us to turn off and then back on the displays automatically, allowing us a workaround, but it still does not solve the core issue of that nouveau is not waking up the monitors.

Please see the attached logs/config files and diagram below for more information.

|Machine A| |Machine B|
\               /
 \             /
  \ _________ /
   |DPort KVM|
   /         \
  /           \
 /             \
|Monitor 2| |Monitor 1|

Version-Release number of selected component (if applicable):
Comment 2 Dhruv Thakkar 2017-06-22 12:09 EDT
Created attachment 1290765 [details]
Comment 3 Dhruv Thakkar 2017-06-22 12:10 EDT
Created attachment 1290766 [details]
xorg.conf for nouveau drivers

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