How do I get native 2560x1600 resolution on M1000M, Ubuntu 16.04

Hi there, I’m using HP Zbook laptop with GeForce M1000M graphics card. I have connected over HDMI port external display Dell U3011 with native resolution 2560x1600. Max resolution I can get from Ubuntu 16.04 is 1600x1200.

From Windows 10, however, using the same setup (Dell U3011 over the same HDMI port), I get full 2560x1600 resolution with no problem.

$ sudo lshw -numeric -C display
  *-display               
       description: VGA compatible controller
       product: GM107GLM [Quadro M1000M] [10DE:13B1]
       vendor: NVIDIA Corporation [10DE]
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a2
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:132 memory:e3000000-e3ffffff memory:a0000000-afffffff memory:b0000000-b1ffffff ioport:3000(size=128) memory:e4080000-e40fffff

PS. I use HDMI to DVI cable, so HDMI end goes to laptop, DVI end goes to external display.
nvidia-bug-report.log.gz (181 KB)

Please set

Option "ModeDebug" "true"

in xorg.conf and rerun nvidia-bug-report.sh.

I added that line at the end of /etc/X11/xorg.conf. Attaching the debug dump.
nvidia-bug-report.log.gz (170 KB)

That doesn’t work. Every option has to be added to a section. Add it to the screen section.

I booted Linux laptop today but unfortunately I don’t have /etc/X11/xorg.conf file anymore. I have xorg.conf.failsafe and xorg.conf.nvidia-xconfig-original, but no xorg.conf. What do I do now? I tried stopping lightdm and doing Xorg -configure, but that also fails saying number of devices vs number of screens doesn’t agree.