[coreboot] Re: No framebuffer available until amdgpu driver is loaded

[Paul Menzel]

Dear Jorge,

On 2019-11-12 15:12, Jorge Fernandez Monteagudo wrote:
> I have a little problem trying to get a vesa framebuffer when booting my system.

What board with what graphics device is it?
> I have the system with the original bios and the vesa fb working. These are the
> relevant dmesg traces:

[…]
> With the system and my modified coreboot I can get a vesa fb working and I get no image on
> screen until the amdgpu driver is loaded and the Xorg is running. The suspicious dmesg traces
> are:
>
> [    0.253527] PCI host bridge to bus 0000:00
> [    0.253529] pci_bus 0000:00: root bus resource [io  0x0000-0x0cf7 window]
> [    0.253530] pci_bus 0000:00: root bus resource [io  0x0d00-0xffff window]
> [    0.253531] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff]
> [    0.253532] pci_bus 0000:00: root bus resource [mem 0x000c0000-0x000dffff]
> [    0.253533] pci_bus 0000:00: root bus resource [mem 0xd0000000-0xffffffff]
> [    0.253535] pci_bus 0000:00: root bus resource [bus 00-ff]
> [    0.253544] pci 0000:00:00.0: [1022:1576] type 00 class 0x060000
> [    0.253640] pci 0000:00:01.0: [1002:9874] type 00 class 0x030000
> [    0.253658] pci 0000:00:01.0: reg 0x10: [mem 0xe0000000-0xefffffff 64bit pref]
> [    0.253666] pci 0000:00:01.0: reg 0x18: [mem 0xf0000000-0xf07fffff 64bit pref]
> [    0.253672] pci 0000:00:01.0: reg 0x20: [io  0x2000-0x20ff]
> [    0.253677] pci 0000:00:01.0: reg 0x24: [mem 0xf0b00000-0xf0b3ffff]
> [    0.253682] pci 0000:00:01.0: reg 0x30: [mem 0xf0b40000-0xf0b5ffff pref]
> [    0.253723] pci 0000:00:01.0: supports D1 D2
> [    0.253724] pci 0000:00:01.0: PME# supported from D1 D2 D3hot
> ...
> [    0.267038] pci_bus 0000:00: resource 4 [io  0x0000-0x0cf7 window]
> [    0.267039] pci_bus 0000:00: resource 5 [io  0x0d00-0xffff window]
> [    0.267041] pci_bus 0000:00: resource 6 [mem 0x000a0000-0x000bffff]
> [    0.267042] pci_bus 0000:00: resource 7 [mem 0x000c0000-0x000dffff]
> [    0.267043] pci_bus 0000:00: resource 8 [mem 0xd0000000-0xffffffff]
>
> In this case the resource 10 related to the mem address 0xe0000000 is not 
> int the pci_bus 0000:00: root bus resource list and is not in pci_bus 0000:00: resourceX
> list... and this is the address related to the framebuffer.
>
> What could it be the source of the problem?

Please always attach the coreboot logs and the CBFS content.

build/cbfstool build/coreboot.rom print

Do you run the VGA Option ROM? Without it, you won’t get any output until
a proper driver sets up the device to my knowledge.

Kind regards,

Paul