Patch Set 1:

The VBIOS Option ROM does not light up the screen, and TianoCore is also not showing anything.

```
PCI: 00:02.0 init
FMAP: area COREBOOT found @ 350200 (4914688 bytes)
CBFS: Locating 'vbt.bin'
CBFS: Found @ offset 705c0 size 4a3
Found a VBT of 6144 bytes after decompression
GMA: Found VBT in CBFS
GMA: Found valid VBT in CBFS
FMAP: area COREBOOT found @ 350200 (4914688 bytes)
CBFS: Locating 'pci8086,5916.rom'
CBFS: Found @ offset 102e00 size 10000
In CBFS, ROM address for PCI: 00:02.0 = 0xffc53048
Copying VGA ROM Image from 0xffc53048 to 0xc0000, 0x10000 bytes
Calling Option ROM...
intel_vga_int15_handler: AX=5f34 BX=0190 CX=0002 DX=03da
intel_vga_int15_handler: AX=5f51 BX=c000 CX=0000 DX=03da
intel_vga_int15_handler: AX=5f40 BX=0000 CX=0004 DX=0008
DISPLAY=0
intel_vga_int15_handler: AX=5f52 BX=400a CX=000f DX=0008
Unknown INT15 function 5f52!
int15 call returned error.
intel_vga_int15_handler: AX=5f49 BX=19ff CX=0000 DX=1dcc
Unknown INT15 function 5f49!
int15 call returned error.
intel_vga_int15_handler: AX=5f49 BX=0050 CX=0300 DX=0040
Unknown INT15 function 5f49!
int15 call returned error.
intel_vga_int15_handler: AX=5f14 BX=078f CX=0002 DX=0008
Unknown INT15 function 5f14!
int15 call returned error.
intel_vga_int15_handler: AX=5f35 BX=c000 CX=0002 DX=03da
... Option ROM returned.
VGA Option ROM was run
PCI: 00:02.0 init finished in 326 msecs
```

According to the BSF script file for the SKL/KBL/CFL/AML VGABIOS, these are the int15 functions called that coreboot does not support:
5f52h: Hook to get Panel Color Depth from Setup (Mobile only)
5f49h: Hook to get the backlight inverter type, polarity and initial brightness
5f14h: Get Miscellaneous Status (Mobile only)

The information provided by the first two should be available in the VBT inside the VGABIOS. You could try using the Intel BMP (Binary Modification Program) to disable these hooks. The last hook is apparently required for DisplayPort Redriver suppoort.

View Change

To view, visit change 43852. To unsubscribe, or for help writing mail filters, visit settings.