Xubuntu 14.04 does not detect second monitor

Question

I have a Dell Latitude Laptop E6440. The laptop have two interfaces, VGA and HDMI. I connect an external monitor to the VGA port, but when I ran the xfce4-display-settings I see only one monitor (the laptop one ofcourse).

How can I make it to recognize the second monitor ? I already tried booting when it is connected. Still no help.

Here is some info:

I am using Xubuntu 14.04:

Linux 3.13.0-30-generic #54-Ubuntu SMP Mon Jun 9 22:45:01 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

I have a dual graphic adapter: One is:

00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller (rev 06)

Second one is:

01:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Sun XT [Radeon HD 8670A/8670M/8690M]

xrandr says:

xxx@dellorian:~$ xrandr 
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1600 x 900, current 1600 x 900, maximum 1600 x 900
default connected 1600x900+0+0 0mm x 0mm
   1600x900       77.0* 

Any idea?

Here is my /var/log/Xorg.0.log post: http://paste.ubuntu.com/7730096/

Solution

Your logs suggest that KMS is disabled through the nomodeset option:

[ 4.409] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.13.0-30-generic root=UUID=87d0f715-ffb9-454e-a1a8-3233df4fa25e ro nomodeset quiet splash vt.handoff=7

Without this option, the Intel (i915) and radeon video driver won't load, and thus fallback to other, more limited options. You should remove this option, it is probably present in /etc/default/grub. Once changed, you have to run sudo update-grub and reboot.

Comments

[Lekensteyn]

Could you post your /var/log/Xorg.0.log file somewhere on paste.ubuntu.com?

[Aviv]

Thanks @Lekensteyn posted it here: paste.ubuntu.com/7730096

[Aviv]

Thanks. Hi. I will try without the nomodeset. I think I had another problem without nomodeset: google-chrome did not detect the hardware graphic accelerator and I couldn't use WebGL.

[Lekensteyn]

@Aviv Well, nomodeset is the worst solution for that, it causes everything to be done in software. Did the alternatives (--ignore-gpu-blacklist iirc) not help in that case? Anyway, did the removal of nomodeset fix your problem?

[Aviv]

Yes, It solved the problem. I can see my second monitor. And even chrome://gpu shows "Hardware Accelerator" - Hence WebGL is working ! - Great Job. Thanks. Maybe you can help with my second question ? askubuntu.com/questions/490121/…

[Aviv]

Hey @Lekensteyn - I posted another question quite on topic. askubuntu.com/questions/503118/google-chrome-crashes-in-14-0‌​4 Can you please look and read my comment too. It will be very helpful. Thanks.