# Intel graphics not working on Macbook Pro in EFI mode

## Splooshie123

Hello.

I have Gentoo installed on a Macbook Pro 6,2 which has integrated Intel graphics and a discrete Nvidia GPU.

```
$ lspci | grep VGA

00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 18)

01:00.0 VGA compatible controller: NVIDIA Corporation GT216 [GeForce GT 330M] (rev a2)
```

With BIOS emulation, the intel gpu isn't even activated (not listed in lspci). So I have to use EFI mode.

The Nvidia gpu works fine in BIOS and EFI mode with no problems.

In EFI mode, the intel gpu is available, but it doesn't work. I get a blank screen with a few graphical artifacts during the whole boot process until the nvidia card kicks in.

These are the relevant kernel parameters kernel parameters:

```
i915.lvds_channel_mode=2 i915.modeset=1 i915.lvds_use_ssc=0
```

Any way I can get it working?

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## Splooshie123

Fixed it.

I had to add this to my grub.cfg before the kernel is loaded:

```
outb 0x728 1

        outb 0x710 2

        outb 0x740 2

        outb 0x750 0
```

The first 3 lines switch to the intel graphics and the last line powers down the nvidia card. I was using the nvidia card the whole time! That's why it didn't work.

The last line is optional. I was able to start X without it. However, powering down the discrete graphics reduces energy consumption by 10 watts (I think per hour. Powertop doesn't say).

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