Re: cg14 vesa (modes) project on github

[Bob Breuer <bbreuer711%gmail.com@localhost>]

On Wed, Jan 7, 2026 at 9:47 PM Andrew Randrianasulu
<randrianasulu%gmail.com@localhost> wrote:
>
>
>
> чт, 8 янв. 2026 г., 06:16 Bob Breuer <bbreuer711%gmail.com@localhost>:
>>
>> On Wed, Jan 7, 2026 at 11:46 AM Andrew Randrianasulu
>> <randrianasulu%gmail.com@localhost> wrote:
>> >
>> > On Wed, Jan 7, 2026 at 8:40 PM Malte Dehling <mdehling%gmail.com@localhost> wrote:
>> > >
>> > > Hi Andrew,
>> > >
>> > > I've only tested the prom on physical hardware, and I haven't been able to get qemu to work with an ss20 and original prom recently.  Would love to hear if you make progress on this!
>> >
>> > well, for me setting -cpu to something like
>> >
>> > "TI SuperSparc 50"
>>
>> As I remember, the Qemu SuperSparc II implementation doesn't support
>> one of the features used by the original OBP roms.
>
>
> May be filling qemu-upstream bug about it will help, eventually?
>
> I noticed that with original ROM -smp switch does not increase about of  firmware-counted CPUs ...
>
>>
>> >
>> > work, at least i see logo and can enter probe-scisi.
>> >
>> > Note, this is more like qemu 9.2.50 as Artyom created it 9 months ago,
>> > not really recent qemu git (10.x, 11.x)
>> >
>> > https://youtu.be/wCFBvzVCVMk - short vid of whole thing booting
>> >
>>
>> I didn't notice that Artyom rebased my cg14 patches.  I also have a
>> separate branch where I implemented the DBRI audio device.
>
>
> Interesting, is this branch public?

Yes, it's here:  https://github.com/breuerr/qemu/tree/dbri-pre2
I think the audio output was clean with a Linux client but had popping
with a netbsd client.

>
>
>>
>> > >
>> > > IIRC, qemu has resolutions hard coded in, but I may be wrong about this.
>>
>> Is there any particular resolution that you are looking for?
>>
>> The emulated cg14 was flexible enough to handle any resolution that
>> could be programmed.  However, the startup resolution is limited by
>> the monitor ID bits.  The cg14_set_monitor_id() function translates
>> the Qemu command line resolution to a monitor ID for a nearby OBP
>> resolution.  In addition to 1152x900, the resolutions of 1280x1024 and
>> 1600x1280 should also work by default.
>
>
> In my case I was after not so much resolution per se, but was trying to avoid some strange emulated  TCX bugs, I can avoid most of them by running xcompmgr& in NetBSD but something still not 100% correct with cinelerra-gg and mplayer, colors are swapped in video output (plain X11, not xv), so I was hoping to see if emulated cg14 can sidestep this issue
>

Might be able to try with cg3, that thing had absolutely no
acceleration, but it's 8-bit only.

Or if you need 24-bit color but the lack of SX is a problem,
theoretically the SS10 supported cg14 without SX and it should be
possible to hack that into qemu.

>
>>
>> Bob
>>
>>
>> > >
>> > > Cheers,
>> > > Malte
>> > >
>> > >
>> > > On Wed, Jan 7, 2026, 9:31 AM Andrew Randrianasulu <randrianasulu%gmail.com@localhost> wrote:
>> > >>
>> > >> On Wed, Jan 7, 2026 at 8:00 PM Andrew Randrianasulu
>> > >> <randrianasulu%gmail.com@localhost> wrote:
>> > >> >
>> > >> > Was looking for Sparcstation-20 proms to test with cg14 enabled qemu
>> > >> >
>> > >> > found this project;
>> > >> >
>> > >> > https://github.com/mdehling/cg14-vesa-mod
>> > >> >
>> > >> > https://github.com/artyom-tarasenko/qemu/ - branch cg14
>> > >> > https://github.com/artyom-tarasenko/qemu/commit/1b1d8b87619e613b059766e6e54687b027fb6e3f.diff
>> > >> >
>> > >> > https://github.com/artyom-tarasenko/qemu/commit/b297821755e68381e7753d877a7912bebe9271d8.diff
>> > >> >
>> > >> > but device cg14 not on list so you need to start it like this:
>> > >> >
>> > >> > build/qemu-system-sparc -M SS-20 -g 1152x900
>> > >> > cg14_realizefn 1152, 900
>> > >> >
>> > >> > Of course default openbios does not know how to output to that, so I'm
>> > >> > trying this Sun PROM now ...
>> > >>
>> > >>
>> > >> It tries to boot my NetBSD install but it faults somewhere along the way:
>> > >>
>> > >>  build/qemu-system-sparc -M SS-20 -g 1152x900 -bios
>> > >> ~/Desktop/ss20-2.25.bin  -cpu "TI SuperSparc 50" -hda
>> > >> /mnt/zip/home/guest/QEMU/sparc-netbsd-15g-compressed-r1.qcow2
>> > >> cg14_realizefn 1152, 900
>> > >> CG14: control register (0x5a) has unimplemented bits set
>> > >> CG14: readb from reg 1000
>> > >> CG14: writeb 0x00 to reg 1000
>> > >> CG14: writeb 0x01 to reg 1000
>> > >> CG14: readb from reg 1000
>> > >> CG14: readb from reg 1001
>> > >> CG14: writeb 0x01 to reg d
>> > >> CG14: readl 00000000 from reg 20c
>> > >> CG14: writeb 0x02 to reg 100
>> > >> CG14: readl 00000000 from reg 20c
>> > >> CG14: readb from reg 200b
>> > >> CG14: readb from reg c
>> > >> CG14: writeb 0x00 to reg c
>> > >> CG14: writeb 0x02 to reg 100
>> > >> CG14: readl 00000000 from reg 20c
>> > >> CG14: readb from reg 200b
>> > >> CG14: readb from reg c
>> > >> CG14: writeb 0x00 to reg c
>> > >>
>> > >> https://mastodon.online/@Andrew_R/115854999356998946