# Why is Ubuntu unable to mount my hard drive when I use Nvidia Discrete graphics?

I have a Lenovo Thinkpad T520 with Nvidia Optimus graphics. Optimus is designed to let you switch between discrete and integrated graphics as needed for performance and battery life.

The BIOS has three options for display: Optimus, Integrated, and Discrete. Integrated and Discrete enable only the Intel or Nvidia chipsets, respectively.

The system boots fine if I selected integrated (or Optimus) graphics in the BIOS, however if I choose Discrete graphics, I'm unable to boot. It appears, weirdly, that when discrete graphics are enabled, Linux is unable to access my hard drive. Here's a screenshot:

Unfortunately, while it appears to dropped to BusyBox, the system is totally unresponsive at that stage and must be rebooted.

The problem persists regardless of whether I've installed Nvidia's drivers, the Open Source Nouveau driver, or both. This is the Nvidia chipset, and the Intel chipset:

00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: NVIDIA Corporation GF119 [Quadro NVS 4200M] (rev a1)

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Interesting. The I/O subsystem and its errors should be totally unrelated to the graphics subsystem. Are you running the latest BIOS update? And do you have any ACPI/OS-specific options in the BIOS? –  gertvdijk Jan 25 '13 at 18:14
In the BIOS, it does have an option to detect whether the OS supports Optimus. That's enabled, and from what I've read, Linux reports itself as supporting it. Either option doesn't work. In terms of ACPI, there are a ton of power options I haven't messed with. What should I be looking for? –  Ken Jan 28 '13 at 15:14
Does it boot when you select "Discrete" graphics in the BIOS? –  Travis G. Jan 30 '13 at 21:40
Travis, this is from when I select Discrete in the BIOS. With Integrated or Optimus, it boots fine; with discrete, it does not. –  Ken Jan 30 '13 at 22:23

I have a discrete Radeon card in an HP Pavilion m6. HP has recently locked the BIOS to only operate in "mixed" mode so I didn't have an option to BIOS disable Intel HD graphics, and here was my workaround.

1. BIOS set to mixed - couldn't change this, but in the end it didn't seem to matter.
2. Synaptic > Settings > Repositories > Additional Drivers

Bingo, under the default xorg option is fglrx proprietary drivers for AMD graphics card.

1. Download base packages from the proprietary from apt-get or Synaptic. When I just tried to switch drivers without doing this the progress bar would hang with no error, so this one is important.