Which of two video drivers am I using?

Question

I am trying to figure out if my integrated intel graphics are being used rather than my discrete GeforceEFORCE 210M. When I check "Additional Drivers" under settings, it does not show any proprietary drivers to be installed indicating that the system doesn't even detect the NVIDIA driver. However,

Runningsudo lshw -c video gives me the result:

 *-display               
       description: VGA compatible controller
       product: GT218 [GeForce G210M]
       vendor: NVIDIA Corporation
       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=nouveau latency=0
       resources: irq:16 memory:fd000000-fdffffff memory:e0000000-efffffff memory:fa000000-fbffffff ioport:dc00(size=128) memory:fe980000-fe9fffff
  *-display
       description: Display controller
       product: Mobile 4 Series Chipset Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 07
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:46 memory:fcc00000-fcffffff memory:d0000000-dfffffff ioport:cc00(size=8)

but it doesn't tell me which of the two is currently being used... so how can I figure this out?

Notes:

• I am on Ubuntu 12.04
• I have not installed any video drivers manually yet.
• I have no xorg.conf (I don't know if this helps or is important, just stating it)
• The hybrid graphics works fine on my Windows 7 partition.

Answer 1

I've added to my system (also a laptop with dual video card) a line in rc.conf to auto reduce the screen brightness at startup, this gave me a clue to make sure which card it's being used:

echo 4 > /sys/class/backlight/acpi_video1/brightness

(you can test this command on command line and if this card is being used you'll see how brightness get reduced, if it doesn't try acpi_video0). Looking inside the subdirectory device found a file called uevent:

$ cat /sys/class/backlight/acpi_video1/device/uevent 
DRIVER=i915

Combined this with the log info (video drivers' names) I'm sure that I'm using the internal video card.

Answer 2

In a terminal type less /var/log/Xorg.0.log and examine the results.

As you go down in the log the name of the driver should become obvious--it will be checking EDID (DDC) information and selecting a mode to use, etc. Different drivers output different things to the log so I can't be specific about specific text to search for.