On 06.08.2017 05:18, Zheng Bao wrote:
At which stage do you want to enables these ports? in the OS? or during boot? if the latter, which payload do you use?
Zheng: I want to enable these display port during boot. The payload is SeaBIOS.
You have to set your VGA BIOS to a VESA mode AFAIK. In text mode, only one display can be enabled. Though, I don't know how to do that with SeaBIOS. There might be a compile time option?
There are also many options inside Intel's VGA BIOS in a structure called Video BIOS Table (VBT). IIRC, you can set it to start in VESA mode with multiple displays there.
There's also an open-source solution for Intel gfx bringup, libgfxinit. Alas, it's not ready to use on Broadwell (it works generally just some steps are missing to make it work with coreboot).
Nico
In text mode, only one display can be enabled.
Can this enabled display port be DDI1 or DDI2?
I just extracted VBIOS from BIOS provided on board. I assume the display ports are enabled based on the board settings.
Can I just set register "gpu_panel_port_select" = "2" to enable DDI1?
Thanks.
Zheng
________________________________ From: Nico Huber nico.h@gmx.de Sent: Monday, August 7, 2017 9:32 AM To: Zheng Bao; coreboot@coreboot.org Subject: Re: [coreboot] [Broadwell-U]How the eDP, DDI1, DDI2 are enabled?
On 06.08.2017 05:18, Zheng Bao wrote:
At which stage do you want to enables these ports? in the OS? or during boot? if the latter, which payload do you use?
Zheng: I want to enable these display port during boot. The payload is SeaBIOS.
You have to set your VGA BIOS to a VESA mode AFAIK. In text mode, only one display can be enabled. Though, I don't know how to do that with SeaBIOS. There might be a compile time option?
There are also many options inside Intel's VGA BIOS in a structure called Video BIOS Table (VBT). IIRC, you can set it to start in VESA mode with multiple displays there.
There's also an open-source solution for Intel gfx bringup, libgfxinit. Alas, it's not ready to use on Broadwell (it works generally just some steps are missing to make it work with coreboot).
Nico
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Nico Huber -
Zheng Bao