AIX screen resolution

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Shiunbird
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AIX screen resolution

Unread postby Shiunbird » Wed Jul 06, 2016 12:53 am

Hello folks, good day!

So I'm resuming my workstation project on my IntelliStation 285.
I wiped out Linux from my second hard drive and installed AIX 5.3.

Now a funny thing... my graphics card (GXT135p) supports 1920x1200 on VGA, and only 1280x1024 on DVI.
AIX 7.1 detects it correctly and I get full resolution on my 1920x1200 display.

But 5.3 treats the VGA port like the DVI one, letting me go up to 1600x1200 30Hz or 1280x1024 60Hx.

I checked Google and some IBM documents and couldn't find where to start from. Any ideas?

Thanks! =)
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Re: AIX screen resolution

Unread postby ibmfiles » Sun Oct 30, 2016 12:05 pm

Here are the features of the "IBM" GXT135P (which by the way is actually a Matrox G450):
Maximum resolutions (per display)
Digital: 1280 x 1024
Analog, main display: 2048 x 1536
Analog, secondary display: 1600 x 1200
http://www.matrox.com/graphics/en/produ ... s/g450pci/


The analog VGA output supports a larger resolution, whereas the digital DVI output can only go to a maximum of 1600x1200 (UXGA). If you're trying to run BOTH outputs, then it's because the secondary one can't exceed 1600x1200 when both ports are in use (which 1920x1200 does). The G450 is pretty old and was one of the earlier 'dual display' adapters-- Matrox in fact pioneered the first video card to feature dual displays; I think that was on the G200. Your answer comes in more detail on wikipedia in regards to the mismatched clock speeds of the RAMDACs:
wikipedia wrote:Perhaps the biggest addition to G450 was that Matrox moved the previously external second RAMDAC, for the second monitor connector (DualHead), into the G450 chip itself. RAMDAC speeds were still different though, with the primary running at an excellent 360 MHz, but the secondary running at only 230 MHz. This meant that the primary monitor could run much higher resolutions and refresh rates than the secondary.


Hope that helps (I know you've already removed the Matrox out anyways).

EDIT: It may be worthy to point out a few things about the G450 which IBM documentation ignores (although since IBM didn't make the card they can leave whatever 'extra' details out as they please). The G400 series did feature "3D" support, it's not a 2D-exclusive accelerator as IBM would have you believe (re: EMBM), and if you look carefully, you'll see solder points for DVI and VGA directly on the PCB--which is why the VGA connectors are longer than normal and 'overreach' over the DVI solder points; this was to ensure a solid clear VGA picture).

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Re: AIX screen resolution

Unread postby Shiunbird » Sun Oct 30, 2016 7:27 pm

Hello ibmfiles, welcome! =)

I'm not really trying to run both outputs at the same time. When I boot AIX 7.1, smit gives me the option to choose 1920x1200x32@60Hz if I boot the system with a VGA display connected. If I boot with the DVI connector active, it naturally gives me only 1280x1024x32@60Hz or 1600x1200x32@30Hz. If I boot the system with both displays connected, I get a mirrored output at 1280x1024.

On AIX 5, if I boot with a VGA display, I only get 1280x1024.

However, anywhere in AIX 5 I find how to define a primary or secondary or whatever monitor. The reason why I asked for help is that, as you mentioned, the outputs are different. I'm not that fluent in AIX to find out how to tweak the settings by digging config files.

Your edit is interesting. I don't find the VGA output that amusing, though. The CDE default wallpapers flicker horribly on the VGA output, although the rest of the content looks solid.
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Re: AIX screen resolution

Unread postby ibmfiles » Sun Oct 30, 2016 11:52 pm

Shiunbird wrote:Hello ibmfiles, welcome! =)

I'm not really trying to run both outputs at the same time. When I boot AIX 7.1, smit gives me the option to choose 1920x1200x32@60Hz if I boot the system with a VGA display connected. If I boot with the DVI connector active, it naturally gives me only 1280x1024x32@60Hz or 1600x1200x32@30Hz. If I boot the system with both displays connected, I get a mirrored output at 1280x1024.

On AIX 5, if I boot with a VGA display, I only get 1280x1024.

However, anywhere in AIX 5 I find how to define a primary or secondary or whatever monitor. The reason why I asked for help is that, as you mentioned, the outputs are different. I'm not that fluent in AIX to find out how to tweak the settings by digging config files.

Your edit is interesting. I don't find the VGA output that amusing, though. The CDE default wallpapers flicker horribly on the VGA output, although the rest of the content looks solid.


VGA on modern LCDs is an interesting battle because there's a lot of things at work. Some aspects that matter in regards to picture clarity and eliminating blurriness:
#1 The type of VGA cable used (depending if it has less or more shielding)
#2 The way the LCD internally interprets analog VGA
#3 What refresh rate the adapter support(s) and is outputting the resolution at

So... on an x86 IntelliStation I had along with the L190 display, I would get a clear picture *only at* 72 Hz, if it was set to 60 Hz it would be slightly fuzzy. However, one day I swapped the cable with a weird DVI-to-VGA cable so I wouldn't have to deal with a dongle, since the cable was more shielded the picture became blurry again and I needed to drop it down to 60 Hz for it to become clear again. You'll have to play with different refresh rates and cables to achieve the 'sweet spot' for a clear picture.

However as you mentioned, I don't know myself about customizing resolutions or refresh rates under AIX, but I can see if someone knows about it. Is it necessary to keep the G450? I'm certain a video card that could run DVI in a higher resolution would be more desirable. I had this crazy idea / the 3dfx Voodoo 5500 cards had a mac release for PPC machines, and 3dfx also released the Linux drivers to open source so they could be ported to AIX. I wonder how well a mac 5500 would fare under AIX / PPC Linux. The 5500 unlike the G450 supports up to 2048x1536, and coincidentally it's dual GPU like the GXT6500P.

I have flashed my mac 5500 with the PC BIOS, so I'd have to reflash it back to the mac BIOS... sort of too lazy to do that at a moment as I recycled the one PC that I had capable of such a feat.

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Re: AIX screen resolution

Unread postby Shiunbird » Mon Oct 31, 2016 10:09 am

AIX doesn't output anything with the flashed Radeon 7000, only Open Firmware and Linux.
The system boots, and the OS loads, but nothing comes on the screen. After OF I get blank. I tried keeping both cards in simultaneously, but then I get a cryptic error code on the front panel and that's it.

AIX doesn't seem to try framebuffer output if there's no specific driver for the card. And there won't be drivers for AIX besides the standard IBM cards I guess.

In regards to the pattern, I guess it's just because of the style of the background in AIX (repeated patterns, and etc), I guess they would have the motion even with a very good cable. It's just how VGA works I guess. Any image I throw in is solid and perfect like DVI, besides the pixelized wallpapers.

I always keep a Mac-flashed card in my drawer just in case. =)
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Re: AIX screen resolution

Unread postby ibmfiles » Sat Nov 05, 2016 11:05 pm

The tdfx x.org drivers are listed here:
https://packages.debian.org/jessie/powe ... x/filelist

Info on the driver here:
ftp://www.x.org/pub/X11R6.8.0/doc/tdfx.4.html

Presumably it should work then, if I ever decide to install PPC Linux on mine I'll do the ROM swap again to return the 5500 back to its Mac state. I was considering getting another Mac 5500 to save myself the trouble from flashing the one I have back to the Mac firmware--but none exist on ebay and the prices are now insane. $99 for a banshee? Also just checked my 3dfx stash to confirm, apparently I have three spare 5500s which would be a total of six. They must have accumulated over the years--I don't remember getting this many.
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Re: AIX screen resolution

Unread postby Shiunbird » Sun Nov 06, 2016 11:46 am

ibmfiles wrote:They must have accumulated over the years--I don't remember getting this many.


If you leave them alone in a bag or drawer, they will reproduce. You've given them enough time alone to mate and for the offspring to grow and mature.
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