Forcing 1600x1024 resolution?

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whatis
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Forcing 1600x1024 resolution?

Post by whatis »

Hello, I've installed qemu with a macOS 10.14.6 host and a dual boot Mac OS 9.2.1/OS X 10.1 guest, and I'm wondering how I can use my guest with a 1600x1024 resolution? I've tried to flag it as a resolution in the command file, but it just returns to a different resolution in software upon bootup and there's no way to change it to 1600x1024. I'm just wondering if there's any way to possibly change that somehow, either in OS 9 or OS X (whatever works)

(the weird resolution is a result of me using an original 22" cinema display with this setup)

here's my command file by the way

Code: Select all

#!/bin/bash
cd "$(dirname "$0")"

./qemu-system-ppc-screamer -L pc-bios -boot c -M mac99,via=pmu-adb -m 512 \
-prom-env 'auto-boot?=true' -prom-env 'boot-args=-v' -prom-env 'vga-ndrv?=true' \
-drive file=MacOS9.2.img,format=raw,media=disk \
-drive file=*.iso,format=raw,media=cdrom \
-netdev user,id=network01 -device sungem,netdev=network01 \
-device VGA,edid=on \
-g 1600x1024x32 \
-full-screen \
-device usb-kbd \
-device usb-mouse \
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Cat_7
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Re: Forcing 1600x1024 resolution?

Post by Cat_7 »

Hi,

The -g setting only affects the initial openbios screen. As you noticed, after that Mac OS takes over. Currently you can only select one of the resolutions available in the monitors/display settings.

Best,
Cat_7
whatis
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Re: Forcing 1600x1024 resolution?

Post by whatis »

Cat_7 wrote: Sun Feb 28, 2021 12:23 am Hi,

The -g setting only affects the initial openbios screen. As you noticed, after that Mac OS takes over. Currently you can only select one of the resolutions available in the monitors/display settings.

Best,
Cat_7
Aw, okay. Thank you for your help though!
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adespoton
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Re: Forcing 1600x1024 resolution?

Post by adespoton »

If you're up for a bit of hex editing, you can change the default resolutions available in the VGA driver; they're stored in hex notation, so it's just a matter of choosing one you don't want to use (eg, 800x600 or 0320 0258 and changing it to 1600x1024 or 0640 0400.
whatis
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Re: Forcing 1600x1024 resolution?

Post by whatis »

adespoton wrote: Mon Mar 01, 2021 5:00 pm If you're up for a bit of hex editing, you can change the default resolutions available in the VGA driver; they're stored in hex notation, so it's just a matter of choosing one you don't want to use (eg, 800x600 or 0320 0258 and changing it to 1600x1024 or 0640 0400.
I'm trying to figure out where that is in the qemu_vga.ndrv file, is that the correct place to look? It doesn't seem to be in there.
Last edited by whatis on Wed Mar 03, 2021 4:28 pm, edited 1 time in total.
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Cat_7
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Re: Forcing 1600x1024 resolution?

Post by Cat_7 »

Yes, that is the correct file.

Best,
Cat_7
whatis
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Re: Forcing 1600x1024 resolution?

Post by whatis »

I've got it, thanks to the both of you for your help.
FredAkbar
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Re: Forcing 1600x1024 resolution?

Post by FredAkbar »

I found the qemu_vga.ndrv file (in qemu-screamer/pc-bios) and changed the 6 instances of 0320 to 05a0 and 0258 to 0384 (trying for 1440x900), but it didn't seem to have any effect, I still have only 800x600 available. Guest is MacOS 9.2.2.

Qemu command:
./ppc-softmmu/qemu-system-ppc -L qemu-screamer/pc-bios -cpu "g4" -M mac99,via=pmu -m 512 -hda macos92.img -boot c -device VGA,edid=on

(that last device arg I stole from OP--do I need that? I wasn't using it last night)

edit: got it to work, see 2 posts down
Last edited by FredAkbar on Sat Mar 06, 2021 7:54 pm, edited 1 time in total.
FredAkbar
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Re: Forcing 1600x1024 resolution?

Post by FredAkbar »

More generally, I've been finding other versions of qemu_vga.ndrv that people have made that claim to support 256 colors (for example), replaced my file with theirs, and relaunched qemu, but still only seeing Millions of Colors and 800x600, so I wonder if it's indicative of a larger problem with how I'm doing this.
FredAkbar
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Re: Forcing 1600x1024 resolution?

Post by FredAkbar »

Scratch that, I got it to work by following the steps in this post.

Notably, the step I was missing was changing "-L qemu-screamer/pc-bios" to "-L /absolute/path/to/qemu-screamer/pc-bios -bios openbios-ppc"
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Cat_7
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Re: Forcing 1600x1024 resolution?

Post by Cat_7 »

What clears thing up is that you need to know you need a different openbios for the screamer builds compared to the default qemu builds.
You cannot mix them up.

Our downloads contain the correct openbios for each build in the pc-bios folder, and so you only need to point to -L pc-bios for qemu-system-ppc to find the suitable openbios. If you build your own, the easiest way to point to them is to copy the executable and corresponding pc-bios folder into a new folder and just use -L pc-bios.

The vga driver has been fixed a long time ago. It is the same for the screamer source as for the default source. You only need to edit it if you want to change the resolutions available.

Best,
Cat_7
PeterD
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Re: Forcing 1600x1024 resolution?

Post by PeterD »

adespoton wrote: Mon Mar 01, 2021 5:00 pm If you're up for a bit of hex editing, you can change the default resolutions available in the VGA driver; they're stored in hex notation, so it's just a matter of choosing one you don't want to use (eg, 800x600 or 0320 0258 and changing it to 1600x1024 or 0640 0400.
How to edit the driver. Can't find the hex number 03200258
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adespoton
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Re: Forcing 1600x1024 resolution?

Post by adespoton »

PeterD wrote: Wed Dec 29, 2021 2:17 pm
adespoton wrote: Mon Mar 01, 2021 5:00 pm If you're up for a bit of hex editing, you can change the default resolutions available in the VGA driver; they're stored in hex notation, so it's just a matter of choosing one you don't want to use (eg, 800x600 or 0320 0258 and changing it to 1600x1024 or 0640 0400.
How to edit the driver. Can't find the hex number 03200258
You're searching inside the qemu_vga.ndrv file you're using? Using a hex editor like 0xEd?
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adespoton
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Re: Forcing 1600x1024 resolution?

Post by adespoton »

Ah; it's the number search that's the problem.

I didn't include the file offsets as that file could change from build to build. Currently, the qemu_vga.ndrv file contains the resolutions at around file offset 16824. The safest one for you to change would be at file offset 16980, changing 00000550 00000300 (1360x768) to, for example, 00000600 00000400 (1600x1024). You can do this on macOS using the freeware editor Hex Fiend, or your favourite hex editor on your host OS of choice.
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Lucss21a
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Re: Forcing 1600x1024 resolution?

Post by Lucss21a »

Whar's the hex values for 1280x800? Thanks
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adespoton
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Re: Forcing 1600x1024 resolution?

Post by adespoton »

0000 0500 0000 0320
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