[SOLVED] QNIX QX2710 27" Monitor with DVI-to-Displayport Adaptor flickering or not displaying

[vaaahl]

I have had a QNIX 2710 27" 1440p monitor since around 2014 when I built my PC. Being a cheaper Korean panel, it only has one Dual-Link DVI output which was fine because my graphics card at the time (a Sapphire R9 290) supported this.
Fastforward to now and I've decided to downsize my setup away from a desktop to a laptop (an M1 MacBook Air as I don't do much gaming nowadays wanted more portability). However, I'd still like to make use of this monitor as it's a good size and resolution for when I want to be productive.

To get this monitor to work with my MacBook, I've decided to daisy chain a DVI-to-Displayport adaptor to a Displayport-to-USB-C adaptor. I decided to do this since I read that that a lot of adaptors are hit and miss with this monitor, but I read about this goFanco Displayport-to-DVI adaptor which had a lot of positive feedback regarding working with this exact monitor. I then thought any Displayport to USB-C adaptor would then work from there.

However, connecting the monitor to the laptop results in a lot of flickering and static (just overall image corruption it seems). Surprisingly, I get more stable results when using a Single-Link DVI cable (as opposed to the Dual Link-DVI cable I got with the monitor) and I'm not sure why.
I've also tried attaching the monitor to a spare PC I have which has an Nvidia Quadro K4200 which has both Displayport and DVI with these results:

• Monitor to Displayport port in K4200 via adaptor - monitor cycles through red, green, blue colours but PC detects a new input
• Monitor directly to DVI - works perfectly

This makes me think the adaptor may be faulty but I've had a few times where I've gotten the MacBook and Qnix monitor to work perfectly until I unplug it (I have no idea why though).
I'd really appreciate any help or ideas for troubleshooting. Thanks

 

[Glenwing]

If you want to run it at 120 Hz pretty much no adapter is going to be guaranteed to reach that at 1440p. However if you're happy with 60 Hz, there are some options available but it needs to be a dual-link DVI adapter. Most standard adapters are single-link only.

https://www.amazon.com/CAC-1510-DVI-D-Active-Adapter-1600P/dp/B07QKM856C/

 

[vaaahl]

If you want to run it at 120 Hz pretty much no adapter is going to be guaranteed to reach that at 1440p. However if you're happy with 60 Hz, there are some options available but it needs to be a dual-link DVI adapter. Most standard adapters are single-link only.

https://www.amazon.com/CAC-1510-DVI-D-Active-Adapter-1600P/dp/B07QKM856C/

Thanks Glenwing,

Yes I'm fine with 60Hz for my usage and I did think the adaptor I have now is a dual-link one, although the Amazon page states single-link since the reviews seem to indicate that it's working for this monitor. I was also wondering if there was any reason why a Single-Link DVI cable was giving better results than the Dual-Link cable that came with the monitor (which works perfectly when connected directly to DVI).

Maybe going for a more expensive option such as the adaptor you suggested may be the best solution, will see if I can find an equivalent in my country (New Zealand).

 

[SpazT]

I've been messing around with a said monitor, that I've got used described as non-working today. It took me some time to realize, that this monitor is supposed to only work in a dual-link setup. Then, I managed to use it with Linux on my laptop with a single link DisplayPort output (with a cheap adapter cable) using a slow refresh rate of 40Hz ( with cvt 2560 1440 40 and feeding the result to xrandr --newmode and --addmode), this kind of made it obvious, that it also works in a single-link setup. But with Windows I hadn't any success and with a M1 Mac it worked but with a lot of flickering.
So I messed around with the EDID to reduce the clock to 165MHz (the maximum for HDMI 1.2) and after that it worked! On Windows as well as on the Mac without any flickering.
What I did is replacing bytes 55 and 56 (dec) with 0x74 and 0x40 (0x4074 = 16500) resulting in the following EDID:

00: 00 ff ff ff ff ff ff 00 23 2f 9b 04 00 00 00 00    ........#/??....
10: 28 15 01 03 a5 3c 22 78 22 6f b1 a7 55 4c 9e 25    (????<"x"o??UL?%
20: 0c 50 54 00 00 00 01 01 01 01 01 01 01 01 01 01    ?PT...??????????
30: 01 01 01 01 01 01 74 40 00 a0 a0 a0 29 50 30 20    ??????V^.???)P0
40: 35 00 55 50 21 00 00 1a 00 00 00 fc 00 44 55 41    5.UP!..?...?.DUA
50: 4c 2d 44 56 49 0a 20 20 20 20 00 00 00 fc 00 0a    L-DVI?    ...?.?
60: 20 20 20 20 20 20 20 20 20 20 20 20 00 00 00 fc                ...?
70: 00 0a 20 20 20 20 20 20 20 20 20 20 20 20 01 11    .?            ??

I converted the hex representation (bytes 128-256 all 0xff) to binary using xxd -r and wrote it to the EDID flash using edid-rw (make sure you are using the right i2c bus, i always first read the data using edid-rw [bus] | xxd to make sure I'm on the right flash) .

This could be called an under-clocking hack (the refresh rate will be around 40Hz), but makes the QNIX QX2710 single link compatible.