[joevt]

I have found one strange behavior with my CMV-535 and Dell P2415Q.

The Dell’s DisplayPort inputs support all CVT-RB calculated timings for 3840×2160 from 30Hz to 60Hz (testing using macOS, SwitchResX, Nvidia Titan X (Maxwell)).
But the CMV-535 converter won’t pass CVT-RB calculated timings for 3840×2160 when the refresh rate is between 35Hz and 44Hz.

The Dell’s HDMI port (which shouldn’t matter for our purposes) supports CVT-RB calculated timings for 3840×2160 up to 38Hz. 50Hz and 60Hz work when using a 594 MHz pixel clock (as stated in the EDID). Maybe other refresh rates will work when they use a 594 MHz pixel clock (need to manually adjust the sync widths or find a timing calculator that can use a fixed pixel clock).

It may be important to ensure that the timing used by your graphics card matches the information from the Display’s DisplayPort EDID instead of the converter’s EDID. For example, the CMV-535 reports this (594MHz, 135kHz, 60Hz)
Modeline…………… “3840×2160” 594,000 3840 4016 4104 4400 2160 2168 2178 2250 +hsync +vsync
The BenQ BL3201PT and Acer XB321HK report this:
Modeline…………… “3840×2160” 533,250 3840 3888 3920 4000 2160 2163 2168 2222 +hsync -vsync
My Dell P2415Q is like this (but it accepts 594 MHz):
Modeline…………… “3840×2160” 533.250 3840 3902 3950 4000 2160 2163 2168 2222 +hsync -vsync

The Adapter reports limits of 600MHz, 136KHz, 61Hz
The BenQ reports limits of 600MHz, 160kHz, 76Hz
The Dell reports limits of 540MHz, 140kHz, 76Hz
The Acer reports limits of 540MHz, 133kHz, 60Hz

The Dell seems to work regardless of the bandwidth limit.
The BenQ’s limits seem fine, but try the 533MHz timing from the DisplayPort EDID anyway.
The Acer’s limits are less than required for 594MHz, so try the 533MHz timing from the DisplayPort EDID instead.

[joevt]

There is zero reason why a g-sync monitor should not be compatible. If it doesn’t work, then they need to fix it. Their engineering department should have tools to use your EDID with a display that is known to work. If the problem is with the EDID, then they should be able to change the firmware to workaround that problem.

[joevt]

If you can get 1080p from PS4 through the converter then you should be able to get 1080p from PC or laptop through the converter. Do you have any other DisplayPort displays to test?

[joevt]

You didn’t say if the monitor receives a signal from the converter when using different resolutions or settings.

Did you try any tests with a Mac or PC with other resolutions above 165 MHz (such as 2160×1440 60 Hz) and below 165 MHz (1920 x 1200 60 Hz or 1920 x 1080 60 Hz)?

[joevt]

0x00044B is the number for Nvidia. I guess that’s for NVIDIA G-SYNC™ monitors. 0x000C03 is for HDMI. It would be interesting if the converter doesn’t work with any G-SYNC monitor…

[joevt]

Shadow, your EDID for the Acer Predator XB321HK also has a 5 byte VSDB but the IEEE registration number is not that of HDMI. Monitor Asset Manager shows it as:

CE vendor specific data (VSDB)
IEEE registration number. 0x00044B
CEC physical address….. 0.1.0.1
Maximum TMDS clock……. 165MHz

But I don’t think Maximum TMDS clock applies to anything other than the HDMI VSDB (IEEE registration number 0x000C03).

I think you should ask SIIG if the adapter works with a display that has that EDID, and if not, can they supply a firmware update to fix the issue?

[joevt]

There’s a link to Entech’s Monitor Asset Manager (moninfo.exe) at
http://nvidia.custhelp.com/app/answers/detail/a_id/2867

It should work on any PC, with either Intel, AMD, or Nvidia graphics that has a DisplayPort connection to your Acer XB271HK. Run moninfo.exe, select your display (real-time), scroll to the bottom where it says “Raw data”, copy everything after that and paste it here. You can remove commas (with search and replace) to save some space.

The EDID for my Dell P2415Q is pasted below. The first 8 bytes (16 hex digits) are always 00FFFFFFFFFFFF00):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[joevt]

[quote author="lucasbrown"]

• 24 Hz, 25 Hz, and 30 Hz were available frequencies (stated by my PS4), but my display’s OSD doesn’t give me any options to switch into those frequency modes.[/quote]

 Aren’t you supposed to select the frequency from the PS4, not the OSD?

I wonder if the EDID of the Acer XB271HK is similar to the BenQ BL3201PT (mentioned above). Can you post the EDID of the XB271HK? I just need the hex bytes.

[joevt]

Update to my theory: I looked at the EDID which causes Monitor Asset Manager app (moninfo.exe) to think the Max Pixel Clock is 165 MHz. I used “AW EDID Editor” from http://www.analogway.com which more clearly shows the relationship between the bytes and the settings in the EDID. In the BenQ DisplayPort EDID, the CE vendor specific data (VSDB) for HDMI (IEEE Registration Identifier 0x000C03) has the minimum size of 5 bytes. It is missing the 7th byte for the max TMDS clock.

Maybe the CMV-535 assumes a max TMDS clock of 165 MHz when the byte is missing, just like Monitor Asset Manager, and won’t output anything greater than 165 MHz.

[joevt]

My current theory is that the BenQ BL3201PT display is incorrectly advertising a max TMDS clock of 165 MHz (ARTA sent me the EDID) and the CMV-535 is incorrectly limiting output resolutions because of that. 165 MHz would only allow resolutions up to around 1920 x 1200 @ 60 Hz just as ARTA found with his testing.

If that is the problem, then the CMV-535 or the BenQ BL3201PT need a new firmware. It’s possible that the SIIG and Gofanco versions of the adapter have the same bad firmware…

I don’t know of any way to override the EDID for 4K 60 Hz DisplayPort between the display and the adapter like the Gefen DisplayPort Detective Plus could for lower resolutions.

[joevt]

Good find. The Gofanco adapter product page:
http://www.gofanco.com/products/hdmi/hdmi-2-0-to-displayport-1-2-converter-pro-hdmi2dp.html

[joevt]

Found another HDM 2.0 to DisplayPort 1.2 adapter for $200:
http://www.siig.com/hdmi-2-0-to-displayport-1-2-converter-4kx2k-60hz.html

It looks very similar to the CMV-535 that I have except the case is rounded and the power supply uses a different connector. The product country of origin is also the same: Taiwan.

I have bought SIIG’s HDMI 1.4 to DisplayPort adapter before. Now they have a HDM 2.0 adapter. They’re based in California.

[joevt]

Mu7ammad tested the Xbox One X and an adapter from gamintech and posted pictures (see above). Any similar adapter should be able to do the same. It doesn’t matter that he used an 8K display, as it accepts a 4K 60 Hz DP input just fine.

[joevt]

The CMV-535 works for me to convert 4K 60Hz HDMI to DisplayPort. You’ve tried different cables. Have you tried different displays?

There’s an Nvidia webpage about how to get EDID at:
 http://nvidia.custhelp.com/app/answers/detail/a_id/2867

The suggested app, Entech’s moninfo.exe appears to work well enough.

You’ll want to compare the EDID for the benq display (for DisplayPort 1.2 and HDMI 1.4 ports), and the four settings of the CMV-535. Use select all, copy, and paste to get the text output.

If the video timings in the EDID from the CMV-535 is much different than the benq for the desired resolution of 4K 60 Hz, then maybe you need to make an override?

Or, what if you connect the benq directly using DisplayPort 1.2 (without the converter), but override the EDID with that from the CMV-535 to see if that EDID is compatible with the benq?

What is the pixel clock of the 1366×768 resolution? I wonder if the DisplayPort connector is falling back from 4 lanes to 2 or 1 lanes?

[joevt]

It sounds like your PC is able to detect a monitor connection on the HDMI 2.0 output and lets you change the resolution setting, but no signal is coming out of the DisplayPort of the CMV-535. The benq doesn’t show any useful error message?

Can you extract the EDID from each of the 4 settings? Do they appear to be reasonable? We could compare to see if there’s a difference in our firmwares.

You might have a bad unit. Or maybe there’s a compatibility issue between it and the benq. Trying other DisplayPort displays would help to eliminate that possibility. It doesn’t even have to be a 4K display…

Did you try setting the resolution to 1920×1080 (with or without changing the dip switches)?

[Author]

Posts