The wiki is being retired!
Documentation is now handled by the same processes we use for code: Add something to the Documentation/ directory in the coreboot repo, and it will be rendered to https://doc.coreboot.org/. Contributions welcome!
Nvidia Optimus is mainly an ACPI feature to control power of the dGPU.
Coreboot 4.6 doesn't support Nvidia Optimus.
Hybrid Graphics / Switchable Graphics
Hybrid graphics is a feature used by a notebook that has two GPUs and a MUX to switch the notebook's panel to one of the GPUs. Only one GPU is active at time, allowing to save power and making display handling on software side easy.
Coreboot does support hybrid graphics and you can select the GPU to use at boot (using a CMOS setting, through nvramtool or nvramcui). Supported Notebooks:
- Lenovo T400/T500
- Lenovo T420/T520
- Lenovo T430/T530
PowerXpress automatically switches the graphics depending on AC/battery state and user preference. Coreboot 4.6 doesn't support PowerXpress.
Dual graphics is a feature used by a notebook that has two GPUs and where the iGPU is connected to the panel and where the dGPU used to offload rendering to. It can be used on MUXed devices and MUXless devices.
Warning: Enabling two GPUs draws significantly more power ! You need Nvidia Optimus to disable the dGPU's power when not in use! Nvidia Optimus hasn't been implemented as of writing this (2018).
- Active both GPUs at boot
- Include the VGA Option ROM for the dGPU (important, as the VGA Option ROM contains configuration data)
- Include the VGA Option ROM for the iGPU or use Native Graphics Init
- On Linux you can use DRI_PRIME=1 to offload 3D rendering to another GPU.
- Lenovo T400/T500
- Lenovo T420/T520/T420s (depends on: https://review.coreboot.org/#/q/project:coreboot+branch:master+topic:_ROM, https://review.coreboot.org/#/c/coreboot/+/22337/)
- Lenovo T430/T530/T430s (depends on: https://review.coreboot.org/#/q/project:coreboot+branch:master+topic:_ROM, https://review.coreboot.org/#/c/coreboot/+/22337/)
Proprietary Option Rom usage
Please note that you have to use the Nvidia/AMD Option Rom to drive the second GPU. For the Intel GPU you are free to use the Option Rom or use Native graphics Init.