I don't really know where to start looking to solve this problem. Searching the web didn't get me very far. I'm not using any special adapter, it's a straight HDMI cable. It's a fresh install of Ubuntu 14.04.3 (later also 15.10). The same monitor, cable and laptop work in Windows.


if I unplug the monitor, then I run

sudo apt-get install --reinstall ubuntu-desktop
sudo reboot now

the first time I login, and the first time i plug the cable in, the second screen works without problems (dmesg still complains about WARN_ON(!wm_changed), but no more i2c i2c-1: sendbytes: NAK bailout.). But as soon as the laptop turns off the screens (standby) or I reboot the machine or I unplug the cable, the second screen doesn't work anymore.

Also, if I reinstall ubuntu-desktop, but power off the laptop with the HDMI cable plugged in, this trick doesn't seem to work.


  • acer Aspire V 17 Nitro - Black Edition (Aspire VN7-792G)
  • GeForce GTX 960m / Intel Graphics
  • the second monitor is connected through the HDMI port

I'm using the proprietary nvidia driver found in the "Additional Drivers" app. But setting that to use the nouveau display driver doesn't help either.



roman@roman-aspire:~$ xrandr --query
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 16384 x 16384
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 382mm x 215mm
   1920x1080      60.0*+   59.9  
   1680x1050      60.0     59.9  
   1600x1024      60.2  
   1400x1050      60.0  
   1280x1024      60.0  
   1440x900       59.9  
   1280x960       60.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

nvidia-settings sees only one screen. nvidia-settings

lshw -c display

roman@roman-aspire:/$ sudo lshw -c display
       description: 3D controller
       product: NVIDIA Corporation
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a2
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list
       configuration: driver=nvidia latency=0
       resources: irq:128 memory:83000000-83ffffff memory:40000000-4fffffff memory:50000000-51ffffff ioport:4000(size=128)
       description: VGA compatible controller
       product: Intel Corporation
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 06
       width: 64 bits
       clock: 33MHz
       capabilities: pciexpress msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915_bpo latency=0
       resources: irq:126 memory:82000000-82ffffff memory:90000000-9fffffff ioport:5000(size=64)

Could someone please point me in a direction?

UPDATE: I've installed 15.10. Installed the "Intel Graphics for Linux" drivers. And it still doesn't work. But now when I click on "Detect Displays" in nvidia-settings, the application segfaults. Don't know if this has any relevance.

dmesg when I plug in the monitor

[46290.977521] WARNING: CPU: 0 PID: 958 at /build/linux-NgsOGa/linux-4.2.0/drivers/gpu/drm/i915/intel_pm.c:3404 skl_update_other_pipe_wm+0x1de/0x1f0 [i915]()
[46290.977522] WARN_ON(!wm_changed)
[46290.977522] Modules linked in:
[46290.977524]  visor usbserial uas usb_storage snd_seq_dummy xt_nat xt_tcpudp veth arc4 rfcomm bbswitch(OE) xt_conntrack ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 xt_addrtype iptable_filter ip_tables x_tables nf_nat nf_conntrack br_netfilter bridge stp llc aufs rtsx_usb_ms rtsx_usb_sdmmc memstick rtsx_usb bnep snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic nls_iso8859_1 hid_multitouch joydev i2c_designware_platform i2c_designware_core acer_wmi sparse_keymap intel_rapl snd_hda_intel x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_codec snd_hda_core kvm_intel nvidia(POE) snd_hwdep kvm crct10dif_pclmul crc32_pclmul snd_pcm aesni_intel uvcvideo aes_x86_64 videobuf2_vmalloc lrw videobuf2_memops ath10k_pci gf128mul snd_seq_midi videobuf2_core
[46290.977546]  glue_helper snd_seq_midi_event ath10k_core v4l2_common ablk_helper cryptd snd_rawmidi videodev ath media snd_seq mac80211 snd_seq_device snd_timer input_leds idma64 virt_dma serio_raw mei_me snd btusb mei cfg80211 soundcore btrtl btbcm btintel bluetooth intel_lpss_pci shpchp acpi_als kfifo_buf industrialio wmi intel_lpss_acpi intel_lpss tpm_crb acpi_pad mac_hid parport_pc ppdev lp parport autofs4 hid_generic usbhid i915 i2c_algo_bit drm_kms_helper drm r8169 ahci mii libahci i2c_hid hid video pinctrl_sunrisepoint pinctrl_intel
[46290.977565] CPU: 0 PID: 958 Comm: Xorg Tainted: P           OE   4.2.0-27-generic #32-Ubuntu
[46290.977566] Hardware name: Acer Aspire VN7-792G/Aspire VN7-792G, BIOS V1.02 09/25/2015
[46290.977567]  0000000000000000 000000007e6118ab ffff880897287628 ffffffff817eae99
[46290.977568]  0000000000000000 ffff880897287680 ffff880897287668 ffffffff8107b9c6
[46290.977569]  ffff880897287730 ffff8808972877d4 ffff88089e3c7000 ffff88089e3c6000
[46290.977571] Call Trace:
[46290.977574]  [<ffffffff817eae99>] dump_stack+0x45/0x57
[46290.977577]  [<ffffffff8107b9c6>] warn_slowpath_common+0x86/0xc0
[46290.977578]  [<ffffffff8107ba55>] warn_slowpath_fmt+0x55/0x70
[46290.977584]  [<ffffffffc014bb9e>] skl_update_other_pipe_wm+0x1de/0x1f0 [i915]
[46290.977592]  [<ffffffff811a2f8c>] ? zone_statistics+0x7c/0xa0
[46290.977597]  [<ffffffffc014bd6b>] skl_update_wm+0x1bb/0x740 [i915]
[46290.977603]  [<ffffffffc014f4be>] intel_update_watermarks+0x1e/0x30 [i915]
[46290.977614]  [<ffffffffc01b7008>] haswell_crtc_enable+0x488/0xa90 [i915]
[46290.977624]  [<ffffffffc01b3e36>] __intel_set_mode+0x916/0xb60 [i915]
[46290.977633]  [<ffffffffc01baba6>] intel_crtc_set_config+0x2b6/0x580 [i915]
[46290.977642]  [<ffffffffc00b2ef5>] ? drm_mode_create+0x25/0x60 [drm]
[46290.977648]  [<ffffffffc00ac4a6>] drm_mode_set_config_internal+0x66/0x100 [drm]
[46290.977655]  [<ffffffffc00b0b39>] drm_mode_setcrtc+0x3e9/0x500 [drm]
[46290.977659]  [<ffffffffc00a1495>] drm_ioctl+0x125/0x610 [drm]
[46290.977665]  [<ffffffffc00b0750>] ? drm_mode_setplane+0x1b0/0x1b0 [drm]
[46290.977667]  [<ffffffff812110b5>] do_vfs_ioctl+0x295/0x480
[46290.977669]  [<ffffffff810885e1>] ? __set_task_blocked+0x41/0xa0
[46290.977671]  [<ffffffff81211319>] SyS_ioctl+0x79/0x90
[46290.977672]  [<ffffffff8108b1f4>] ? SyS_rt_sigprocmask+0x74/0xc0
[46290.977673]  [<ffffffff817f1c72>] entry_SYSCALL_64_fastpath+0x16/0x75
[46290.977674] ---[ end trace 83ee13270bae676a ]---
[46294.680523] [drm] GMBUS [i915 gmbus dpb] timed out, falling back to bit banging on pin 5

and then an endless:

[46295.906998] i2c i2c-1: sendbytes: NAK bailout.
  • You could try going into the BIOS and setting the graphics mode to Intel-only or Nvidia-only. Also try updating the BIOS. – QwertyChouskie Feb 20 '16 at 23:09
  • @user4901968 Thanks for the idea. I've updated the bios to the latest version. Unfortunately that didn't change anything and the bios doesn't offer me an option to select a GPU – Roman Feb 22 '16 at 9:00
  • Can you try blacklisting i2c? See askubuntu.com/questions/110341/how-to-blacklist-kernel-modules – QwertyChouskie Feb 23 '16 at 2:14
  • uhm, lsmod doesn't show any i2c. – Roman Feb 23 '16 at 15:46
  • 2
    Try going back to 14.04. Do not install any intel drivers that are not available from official repositories through apt-get. Do not configure you X server to use nvidia drivers - use intel drivers. Make sure your /etc/X11/xorg.conf does not contain any "Device" section with "nvidia". Then try again if the monitor works. – nsilent22 Feb 23 '16 at 20:03

I would try following in case the installation is a bit overdone:

sudo apt-get install ppa-purge
sudo apt-get purge nvidia*
sudo ppa-purge ppa:xorg-edgers/ppa
sudo reboot

Back into terminal, simply try this only:

sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update

then this here:

sudo apt-get install nvidia-358 nvidia-prime
sudo apt-get install --reinstall xserver-xorg
  • Just tried this. nvidia-358 doesn't seem to help - nor does 361 (tried that too) – Roman Feb 26 '16 at 16:40

I would install ARandR and use that GUI instead of NVIDIA or others. It works fine for me to set and keep resolutions using multiple monitors on Ubuntu flavors of linux.

Open a terminal window and install:

sudo apt-get update && sudo apt-get install arandr

Then to start using simply find arandr as an app listed in your applications menu. After installation, find it in the menu :

System -> Preferences -> ARandR

Homepage of ARandR : http://christian.amsuess.com/tools/arandr/

All the best ..

  • 1
    arandr doesn't see the other monitor, just like the default ubuntu display settings thingy – Roman Feb 24 '16 at 13:07

Could be driver or Xserver issue? Maybe try:

sudo apt-get remove purge nvidia*
sudo reboot

boot with nouveau drivers (in grub add 'nomodeset' to the end of the linux line)

sudo apt-get install nvidia-current nvidia-current-updates

^ Or replace 'current' with the driver version you're using (I think latest is 352?)

Use ctrl+alt+1-7 to open tty1-7

sudo apt-get install --reinstall xserver-xorg

sudo reboot

Don't add 'nomodeset' on this reboot

This may not fix it but I suppose you should make sure it's just not broken drivers

  • During the last days I've installed and reinstalled pretty much anything. Formatting the disk and reinstalling various Ubuntu versions. Reinstalling nvidia-anything and xserver-xorg did not help. Thanks anyway – Roman Feb 26 '16 at 16:42
  • Sorry it didn't work for you... It never hurts to check! @Roman – Gabriel Ruoff Feb 26 '16 at 19:33

Try the OEM driver, download it here. You will need to kill your graphical sessions, and login as root. you can do this, provided you have permission, by pressing ctrl+alt+F5 then login, and do: sudo -i Next, kill the sessions with kill -9 lightdm you may need to make the script you downloaded execute-able. you can do this with chmod +x <script-name> then, execute the driver install script. Follow the directions, and install the GPU drivers. once it completes, you can run lightdm or startx to see if the changes have improved your situation.

You can go to system-> properties-> displays

to see if your monitors are detected.

You may also want blacklist the Intel drivers, where you are trying to use the NVIDIA GPU instead.

  • Iv'e tried this before, but after installing the OEM drivers I can't get past the login screen (xorg, lightdm or whatever crashes). Did I miss something? – Roman Feb 26 '16 at 16:46

I had this problem in the past.

The only Kernel that I was able to get an external monitor working with (every time) on my V15 Nitro is 4.7.2.

I dug for days to try and get to the bottom of it. Don't even remember if it was trial and error or piecing together multiple sites or whatnot, but that's the only solution I've come across. Hope it helps.


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