Re: [Qemu-ppc] Booting Lubuntu 16.04 on qemu-system-ppc produces errors

[BALATON Zoltan]

On Wed, 10 Jul 2019, Howard Spoelstra wrote:
> qemu-system-ppc -M mac99,via=pmu -L ../queue-vga/pc-bios -cdrom
> /mnt/sdb1/PPC-img/lubuntu-16.04-desktop-powerpc.iso -m 512  -display
> sdl,gl=on -vga std -d guest_errors,unimp -boot d -cpu G4 -g 1024x768x24
> -device ES1370
>
> Hi,
>
> With this simple command line I get to the desktop with Lubuntu PPC 16 32
> bit. Takes some time... Qemu-system-ppc is from current rc0 master.
> Colors are inverted, though.

I got same result on x86_64 Intel host/QEMU but I think the crash Andrew 
reported was with x86_64 host (AMD CPU if that matters) but 32bit x86 
QEMU. So we haven't really tested the same config so we could only confirm 
it does not crash on 64bit host/QEMU.

> ./qemu-system-ppc \
> -L pc-bios \
> -boot d -M mac99,via=pmu -m 1024 \
> -prom-env 'auto-boot?=true' -prom-env 'boot-args=-v' -prom-env
> 'vga-ndrv?=false' \
> -drive
> file=~/Linux-images/lubuntu-16.04-desktop-powerpc.iso,format=raw,media=cdrom
> \
> -serial stdio  \
> -g 1024x768x32 \   (also with x16 and x8)
> -device ati-vga,id=rage128p

I would not call that a simple command as it has a lot of unnecessary or 
ineffective options. My simple command is just:

qemu-system-ppc -M mac99,via=pmu -m 1024 -cdrom 
lubuntu-16.04-desktop-powerpc.iso -boot d -device ati-vga

which gives the same result on x86_64 host and QEMU: boots to desktop 
slowly with swapped endian colors. (The slowness may be due to it trying 
to detect missing hardware, it even tries to talk to modems on serial.) 
All the other options can be omitted:

-prom-env 'auto-boot?=true' is default so unless you want to say false you 
don't need this

-prom-env 'boot-args=-v' is only understood by OSX's mach_kernel AFAIK so 
not useful here

-prom-env 'vga-ndrv?=false' prevents OpenBIOS to add ATY,NDRV to device 
tree but this is only used by MacOS I think so it does not make a 
difference for Linux

-device ati-vga,id=rage128p ati-vga does not use id property and the 
default for it is rage128p now so no other option is needed to get that. 
(It accepts ,model=rage128p but not needed as that's the default.)

-g 1024x768x32 only decides the OpenBIOS screen mode, Linux will switch 
via its own driver and end up in 1024x768x15 mode (after switching through 
all bit depths as can be seen if you enable DEBUG_ATI in 
qemu/hw/display/ati_int.h) so it does not matter what you specify here and 
can be omitted.

> I do have a PowerMac3,1 with ati rage128Pro card available.

What would help if you could try these isos on real PowerMac3,1 with 
rage128pro and see which of them behaves differently on QEMU and how. 
That would help finding emulation bugs and avoid chasing bugs in isos that 
don't work on real hardware either.

Regards,
BALATON Zoltan