[openfirmware] Troubleshooting VGA under qemu?

Marcin Cieslak saper at saper.info
Wed Sep 30 10:04:36 CET 2015


Hello,

I have tried running ofw without BIOS
(as per http://www.openfirmware.info/Building_OFW_for_QEMU)
and it seems that VGA support does not work.
I am using config-virtualbox.fth as advised.

I have uncommented "console-serial" in config.fth 
to be able to interact with the console and run:

    qemu-system-i386 -m 32 -bios emuofw.rom -hda fat:. -serial stdio

(this qemu 2.4.0 on FreeBSD/amd64)

"show-devs" reports (this is with video.fc included)

ok show-devs
/cpus
/dropin-fs
/flash at fff80000
/pci
/dropin-fs
/mmu
/memory at 0
/aliases
/options
/openprom
/chosen
/packages
/cpus/cpu at 0
/pci/ethernet at 3
/pci/display at 2
/pci/pci8086,7113 at 1,3
/pci/pci-ide at 1,1
/pci/host at 0
/pci/isa at 1
/pci/pci-ide at 1,1/ide at 1
/pci/pci-ide at 1,1/ide at 0
/pci/pci-ide at 1,1/ide at 1/cdrom at 0
/pci/pci-ide at 1,1/ide at 0/disk at 0      
/pci/isa at 1/ide-controller at i1f0
/pci/isa at 1/sound at i220
/pci/isa at 1/rtc at i70
/pci/isa at 1/8042 at i60
/pci/isa at 1/fdc at i3f0
/pci/isa at 1/parallel at i378
/pci/isa at 1/serial at i2f8
/pci/isa at 1/serial at i3f8
/pci/isa at 1/timer at i40
/pci/isa at 1/interrupt-controller at i20
/pci/isa at 1/dma-controller at i00
/pci/isa at 1/ide-controller at i1f0/ide at 1
/pci/isa at 1/ide-controller at i1f0/ide at 0
/pci/isa at 1/ide-controller at i1f0/ide at 0/<Unnamed>@0
/pci/isa at 1/8042 at i60/mouse at aux
/pci/isa at 1/8042 at i60/keyboard at kbd
/pci/isa at 1/fdc at i3f0/disk
/packages/http
/packages/tcp
...

I have tried uncommenting

    in: ${BP}/dev/video/build/video.fc

in cpu/x86/pc/emu/emuofw.bth

as well as uncommenting

    create use-vga

in cpu/x86/pc/emu/config.fth, none of which
improves the situation.

When I switch consoles in qemu the VGA screen
says "Guest has not initialized the display (yet)"

Any hints to troubleshoot this?

Additional questions:

1) Would that be possible to have a dual-console mode
(similar to what FreeBSD early bootloader has) so that
both vga and serial console are active? ofw prints
messages on the serial console even if disabled, only
input is not working.

2) Initially I thought ofw is completely dead
and I have run it under gdb, only to figure out
I am running in the Forth inner interpreter:

   0xff9fc000:  lods   %ds:(%esi),%eax
=> 0xff9fc001:  jmp    *(%eax)

Is there any way to have "symbol table" to
map word addresses to the word names? (I figured
out I can tick the word to get its address).

Thank you,
Marcin



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