User:GNUtoo/X60 GPU init

Native GPU init

With the native (intel) GPU initialisation, coreboot itself initialises the GPU.

Initialisation method	Free software, based on	Advantages	Drawbacks
non-free VGA option rom	No, extracted from the BIOS.	compatible with everything works with the official coreboot.	non-free even yabel cannot contain it
Linux kernel i915 driver	Yes, in the linux kernel	works with the official coreboot.	The screen content is only visible after the i915, so you cannot see grub. It worked with trisquel6 kernel, and had issues with some recent kernels. TODO: investigate the memory_corruption_check kernel parameter.
Native GPU initialisation (by coreboot)	Yes, based on a replay of the kernel initialisation	compatible payloads can use the screen.	not in the official coreboot yet. only compatible payload will be able to use the screen, like: libpayload based payloads recent grub versions

Related historic git trees

• http://git.stuge.se/?p=gnutoo-chromiumos-coreboot.git;a=summary : it's an historic tree, containing code that is based on the replay of the option rom, before the native GPU init worked(so it doesn't work).
• http://git.stuge.se/?p=gnutoo-i915tool-x60.git;a=summary : contains an historic version of the i915tool
• http://www.gitorious.org/gnutoo-for-coreboot/coreboot/ : I pushed there the code that I useed. It was often pushed BEFORE trying it on real hardware.

I often contained work on the following topics:

• Native GPU init for i945
• The fallback mecanism
• The removal of the microcode

So I often have cherry-picked patches from gerrit and have some updated copies of some of them. The microcode removal is probably not in gerrit because it won't be accepted as-is, instead the microcodes have to be moved/removed in a cleaner way for master