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[joevt]

I have at my disposal three adapters - two dual link DVI-D and one single link DVI-D.
I also have two HDMI cables - one thicker and one thinner. Where they come from and who made them, I have no idea.

With all possible permutations:
* 2 dual link adapters
* 1 dual link and 1 single link adapter
* single link at Mac end
* single link at display end
I got normal picture (given the U2412M oddities) with thicker HDMI cable.

Dual Link Adapters are just Single Link with unused pins because HDMI is always Single Link.

If you have a GPU that outputs Dual Link DVI (pixel clock > 165 MHz) then you need a Dual Link DVI display or a Dual Link DVI to DisplayPort Adapter to use such display modes.
 https://gefen.com/product/dual-link-dvi-to-mini-dp-converter/

For example, My Nvidia GeForce 7800 GT Mac Edition can output 4K30 or 1440p60 using the Gefen adapter.

To get a Dual Link DVI to HDMI adapter for pixel clocks between 165 MHz and 330 MHz, you need a Dual Link DVI to DisplayPort Adapter and a DisplayPort to HDMI 1.4 or Later adapter.

Of course, Power Mac Mac minis are all limited to Single Link DVI.

[joevt]

Just see how much you can do with 3440x1440 in Mac OS 9
Getting hardware acceleration working on this machine would be awesome!

Not sure how 3440x1440 is possible. What display? What refresh rate? What GPU? What connection type/cable/adapter?

I think the refresh rate would have to be 30Hz to get below the 165 MHz max Single Link DVI timing.

SwitchResX can show the timing info in OS X. Maybe the display has an onscreen menu to show the input signal resolution/refresh rate? Open Firmware might have a command to list all the display modes.

[Knezzen]

Yea, it’s 30Hz but it works fine as a bare framebuffer and it works with hardware acceleration in Tiger. It’s the modified drivers in OS9 that makes it all flickery.

The GPU is whatever the ”silent upgrade” mini has. My machine has 64mb VRAM.
I'll check the timing info with SwitchResX when I get home  

The monitor is a LG 34UM95 connected to the Mini with a DVI to HDMI cable. https://www.lg.com/uk/monitors/ultrawide/34um95-p/

[Knezzen]

Exported my monitors EDID using SwitchResX and attached it to this post.
Also tried putting the ATi extensions back into my Extensions folder and tried all my monitors resolutions using SwitchRes in Mac OS 9. The common denominator is the 30Hz modes (see attached screenshot). All of them gives me a flickering display like in the video I linked to above. All of the resolutions work fine in Tiger on the same machine. It's almost as 30Hz is not really 30Hz outputted when the drivers are active.

Writing this in 1280x1024 works fine and I have hardware acceleration, but the resolution looks really stretched and strange on my monitor. Oh well, what to do.

This is what System Profiler in Tiger says about my GPU:

Code: [Select]

ATI Radeon 9200:

  Chipset Model: ATY,RV280
  Type: Display
  Bus: AGP
  VRAM (Total): 64 MB
  Vendor: ATI (0x1002)
  Device ID: 0x5962
  Revision ID: 0x0001
  ROM Revision: 113-xxxxx-134
  Displays:
34UM95:
  Resolution: 3440 x 1440 @ 30 Hz
  Depth: 32-bit Color
  Core Image: Not Supported
  Main Display: Yes
  Mirror: Off
  Online: Yes
  Quartz Extreme: Supported
  Rotation: Supported
  Television: Yes

[ssp3]

Knezzen, you're expecting way too much from the good old Mini and OS9. In OS9 years nobody knew anything about ultra-wide 3440 x 1440 displays. Get a 19 incher and you'll be fine 

I'm kidding, of course. As I said before, we need somebody who understands this driver stuff and can decompile/recompile it.
I've tried to understand what's going on there and spent some time steering at various ATI drivers in disassembler, but that was a bit over my head, so I gave up.

[joevt]

Exported my monitors EDID using SwitchResX and attached it to this post.

Which version of Mac OS X did you use SwitchResX with?

Also tried putting the ATi extensions back into my Extensions folder and tried all my monitors resolutions using SwitchRes in Mac OS 9. The common denominator is the 30Hz modes (see attached screenshot). All of them gives me a flickering display like in the video I linked to above. All of the resolutions work fine in Tiger on the same machine. It's almost as 30Hz is not really 30Hz outputted when the drivers are active.

That OS 9 screen shot has many modes that are not in the EDID. Where do they come from?

These are the modes in the EDID (sorted by pixel clock):

Code: [Select]

  25.175000 MHz    640x480    59.940476 Hz   4:3     31.469 kHz       DMT 0x04: 
  25.175000 MHz    640x480    59.940476 Hz   4:3     31.469 kHz       VIC   1 : 
  27.000000 MHz    720x480    59.940060 Hz   3:2     31.469 kHz       DTD 5   : 
  27.000000 MHz    720x480    59.940060 Hz  16:9     31.469 kHz       VIC   3 : 
  40.000000 MHz    800x600    60.316541 Hz   4:3     37.879 kHz       DMT 0x09: 
  65.000000 MHz   1024x768    60.003840 Hz   4:3     48.363 kHz       DMT 0x10: 
  74.250000 MHz   1280x720    60.000000 Hz  16:9     45.000 kHz       DMT 0x55: 
  74.250000 MHz   1280x720    60.000000 Hz  16:9     45.000 kHz       DTD 4   : 
  74.250000 MHz   1280x720    60.000000 Hz  16:9     45.000 kHz       VIC   4 : 
  81.624000 MHz   1152x864    60.000000 Hz   4:3     53.700 kHz       GTF     : 
  83.500000 MHz   1280x800    59.810326 Hz  16:10    49.702 kHz       DMT 0x1c: 
 108.000000 MHz   1280x1024   60.019740 Hz   5:4     63.981 kHz       DMT 0x23: 
 108.000000 MHz   1600x900    60.000000 Hz  16:9     60.000 kHz       DMT 0x53: 
 146.250000 MHz   1680x1050   59.954250 Hz  16:10    65.290 kHz       DMT 0x3a: 
 148.500000 MHz   1920x1080   60.000000 Hz  16:9     67.500 kHz       DMT 0x52: 
 148.500000 MHz   1920x1080   60.000000 Hz  16:9     67.500 kHz       VIC  16 : 
 157.750000 MHz   3440x1440   29.992775 Hz  43:18    43.819 kHz       DTD 2   : 
 185.580000 MHz   2560x1080   59.999534 Hz  64:27    66.659 kHz       DTD 3   : 
 265.250000 MHz   3440x1440   49.986808 Hz  43:18    73.681 kHz       DTD 1   : 

Of course, you won't be able to use modes > 165 MHz with DVI single link unless it's actually HDMI 1.4.

Writing this in 1280x1024 works fine and I have hardware acceleration, but the resolution looks really stretched and strange on my monitor. Oh well, what to do.

Your monitor should have an on screen menu option to use "square pixels" or "1:1" or "aspect" or "pillar box" or something.

The only 30Hz mode in the EDID is:

Code: [Select]

    DTD 2:  3440x1440   29.992775 Hz  43:18    43.819 kHz    157.750000 MHz (800 mm x 335 mm)
                 Hfront   48 Hsync  32 Hback   80 Hpol P
                 Vfront    3 Vsync  10 Vback    8 Vpol N

Try some tests in Mac OS X. Duplicate the mode but change the H/V sync polarity from P/N to P/P, N/N, and N/P to see if they all work or if one of them reproduces the problem in Mac OS 9.

I don't think the Mac OS 9 version of SwitchRes lets you create custom timings? If not, then one would probably have to use some Display Manager APIs or call the graphics driver directly (there is cscGetDetailedTiming and cscSetDetailedTiming status and control calls). What is AVComponents.h? Probably something to do with the Monitor & Sounds control panel?

[Knezzen]

Which version of Mac OS X did you use SwitchResX with?

Mac OS X 10.4.11.

That OS 9 screen shot has many modes that are not in the EDID. Where do they come from?

No idea. Might be some kind of calculated max frequency from the GPU? It's the resolution I get in Tiger as well as when running without ATi extensions in Mac OS 9 (using only the frame buffer). I haven't modified anything. Booted the machine and there it was, 3440x1440@30Hz.

Your monitor should have an on screen menu option to use "square pixels" or "1:1" or "aspect" or "pillar box" or something.

Sure, but that doesn't solve the problem. There's obviously something "wrong" or not "optimal" with the modified ATi drivers in Mac OS 9 compared to how the machine acts with the same monitor running with the Tiger drivers in Tiger and without any drivers at all in Mac OS 9. Setting the monitor to 1:1 solves the stretching screen, but not the root problem.

Try some tests in Mac OS X. Duplicate the mode but change the H/V sync polarity from P/N to P/P, N/N, and N/P to see if they all work or if one of them reproduces the problem in Mac OS 9.

You might be on to something here! I'll give that a go later today

[ssp3]

There's obviously something "wrong" or not "optimal" with the modified ATi drivers in Mac OS 9 compared to how the machine acts with the same monitor running with the Tiger drivers in Tiger and without any drivers at all in Mac OS 9.

Knezzen, you're barking up the wrong tree. There's nothing wrong with modified ATi drivers in Mac OS 9, it's just that the driver (hacked ATI extension) responsible for acceleration (ATY,RockHopper2) is from 10.3.7 and it knows nothing about higher resolution displays.
Several people, myself included, tried to hack/copy&paste the same driver from 10.4.x into OS9 extension, but we all failed. It does not work in OS9. I've also compared disassembled 10.3.7 and 10.4.x drivers and tried several mods on newer one based on my intuition, but at the end I concluded that the driver stuff is not my thing.
Search forum for posts by darthnvader, all the details are there. And you're welcome to try it yourself. All RockHopper2 drivers from OSX could be found on ELNs Github.

[Knezzen]

Yeah, you're probably right.

To get some kind of reference point I connected the monitor to my PowerBook G4 Titanium 1Ghz (which has a ATi Radeon 9000 64Mb) using the same DVI to HDM cable as I've used with my Mini. Running the PowerBook in "Clamshell mode" I get the same results as I did with the Mini, but without the distorted 3440x1440@30Hz resolution being available in Mac OS 9. If I disable the ATi drivers in Mac OS 9 I get 3440x1440 unaccelerated (framebuffer) and with the ATi drivers loaded I get up to 1920x1200 in the monitors control panel. 3440x1440@30Hz works with full acceleration in OS X 10.4.11 of course, just like with the mini.

Well, that's it I guess. Putting my hope towards the future. We'll see what happens