1. Can you provide complete dump of cbfs content which is displayed at end of make.
2. Check menuconfig or open .config in your favorite editor & check there for file name.
3. This link might be of help: https://www.coreboot.org/SeaBIOS#Adding_a_VGA_option_ROM & https://www.coreboot.org/VGA_support#How_to_retrieve_a_good_video_bios
4. You need not add both vbios & vbt. Either go with vbios or with vbt. If you plan to use Seabios as payload then vgabios should be fine. And let SeaBios run VGA bios to init display. Refer link above on how to add them.
If you intend to go with vbt.bin then check if extracted vbt.bin is correct or not by comparing it with https://github.com/intel/FSP/blob/master/CometLakeFspBinPkg/CometLakeV/Sampl...
Also you mentioned about custom board, check if PWM signal from SoC is properly connected to eDP connector(This depends on panel), If you have Oscilloscope, then check for PWM signal. It should be high or wave with some duty cycle. This starts only after proper display init. Also check VR's related to eDP backlight are able to turn on & provide right power to LED backlight.
Regards, Naresh Solanki
On Mon, Nov 23, 2020 at 8:55 PM Andy Pont andy.pont@sdcsystems.com wrote:
Hello,
I’m trying to find and fit all of the pieces together to get the display running on my custom platform (based on Intel Comet Lake). Here are the known facts...
- The LCD including the backlight enable and PWM signals are all
connected to the eDP interface on the SoC.
- When I booted the board using the regular AMI BIOS lspci reported: 00:02.0 VGA compatible controller [0300]: Intel Corporation Device
[8086:9bca] (rev 04) (prog-if 00 [VGA controller]) DeviceName: Onboard - Video Subsystem: Device [1e50:800b]
- I have managed to extract a VGA BIOS from the AMI BIOS file but the
PCIR structure lists Vendor ID: 0x8086, Device ID: 0x0406
- I have also managed to extract a VBT binary from the AMI BIOS file
and have included it in the Coreboot image:
In the debug output when booting there are some VGA related messages:
POST: 0x73 found VGA at PCI: 00:02.0 Setting up VGA for PCI: 00:02.0 Setting PCI_BRIDGE_CTL_VGA for bridge DOMAIN: 0000 Setting PCI_BRIDGE_CTL_VGA for bridge Root Device
POST: 0x75 PCI: 00:02.0 init FMAP: area COREBOOT found @ 490200 (11992576 bytes) CBFS: Locating 'vbt.bin' CBFS: 'vbt.bin' not found. FMAP: area COREBOOT found @ 490200 (11992576 bytes) CBFS: Locating 'pci8086,9b41.rom' CBFS: 'pci8086,9b41.rom' not found. PCI Option ROM loading disabled for PCI: 00:02.0 GMA: locate_vbt_vbios: c3e1 d591 6a 52 5f GMA: VBT couldn't be found
Questions…
- Why is the debug output claiming there is no vbt.bin file when it is
lised in the output at the end of the built (Size 1168 LZMA, 4608 decompressed)?
- Why is it searching for pci8086,9b41.rom? I haven’t defined this and
the only reference I can see is in the system76/lemp9/Kconfig file?
- Why doesn’t the VGA BIOS that I have extracted from the AMI BIOS file
match the PCI VID/DID of the VGA controller?
- What else am I missing in order to get the screen to light up?
-Andy.
coreboot mailing list -- coreboot@coreboot.org To unsubscribe send an email to coreboot-leave@coreboot.org