Mode changes fail unless some xorg.conf screen options are set

[Boris Gjenero]

The first mode change always works, but subsequent mode changes keep failing. Running xrandr --output DVI-I-2 --mode 1600x1200 to go back to the native resolution or any other supported resolution fails with:

xrandr: Configure crtc 0 failed
X Error of failed request: BadValue (integer parameter out of range for operation)
  Major opcode of failed request: 140 (RANDR)
  Minor opcode of failed request: 21 (RRSetCrtcConfig)
  Value in failed request: 0x0
  Serial number of failed request: 38
  Current serial number in output stream: 38

Mode changes from SDL 1.2 and 2.0 also fail, and a SDL 1.2 program is killed by the error when returning from full screen.

These are changes for modes on my first monitor, which I use all the time. I think the bug is happening because the second monitor provides invalid EDID while turned off via the switch on the back. Everything works if the switch on the back of the second monitor is turned on or if an /etc/X11/xorg.conf file with sufficient options in the screen section is in place. Ubuntu upgrades rename the xorg.conf file and deactivate it, and I was running into the bug because of that. I'm not yet sure which option lines in the screen section are required. I'm attaching my normal xorg.conf file, which makes things work. I'm calling this a bug because the second monitor shouldn't break mode changes on the first monitor.

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: nvidia-340 340.101-0ubuntu0.16.10.1
ProcVersionSignature: Ubuntu 4.8.0-41.44-generic 4.8.17
Uname: Linux 4.8.0-41-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
ApportVersion: 2.20.3-0ubuntu8.2
Architecture: amd64
CurrentDesktop: XFCE
Date: Fri Mar 10 15:12:33 2017
SourcePackage: nvidia-graphics-drivers-340
UpgradeStatus: Upgraded to yakkety on 2016-10-13 (148 days ago)
modified.conffile..etc.modprobe.d.nvidia-340_hybrid.conf: [deleted]

[dino99 (9d9)]

This is an unsupported release now. Please think to install the next LTS 'Bionic 18.04'

http://cdimage.ubuntu.com/ubuntu-next/daily-live/current/
https://www.omgubuntu.co.uk/2018/02/ubuntu-18-04-minimal-install-option

[Simon Quigley (tsimonq2)]

Marking as Invalid because the release is EOL is not correct. Marking as Incomplete. Also, 18.04 is (at the time of writing) still in development, and you should expect some breakage.
https://wiki.ubuntu.com/Bugs/Responses#Release_has_reached_End_of_Life_.28EOL.29

Reporter, is this still present on 17.10 or 16.04?

[Launchpad Janitor (janitor)]

[Expired for nvidia-graphics-drivers-340 (Ubuntu) because there has been no activity for 60 days.]