PG32UCDP: MCM106 breaks 4k/1080p @ 25Hz/24Hz/23,98Hz and 720p in general for HDMI.

[MA77HIAS]

Like the subject says, the MCM106 firmware update broke the 25Hz, 24Hz and 23,98Hz refresh rates for 4k and 1080p resolutions as well as 720p in general for HDMI. On DP, all resolutions and refresh rates still work just fine, this is limited to both HDMI ports.

I have confirmed this with both a Google TV Streamer and a NVIDIA Shield Pro (2019). Both are now unable to switch to the mentioned refresh rates/resolutions.

This issue completely breaks Android TV's frame frate matching (which Netflix uses). When Netflix tries to switch to one of the refresh rates, the content starts playing but the display stays black and does not react to any of its hardware buttons until one stops the playback and the system switches back to 4k @ 60 Hz for example.

This worked just fine with MCM101 and MCM103.

I would kindly ask for a fix in a future firmware update since, at least for me, this new bug is a major issue and a letdown. 😞

[Aureliannn_ROG]

Hi @MA77HIAS ,

Thank you for your feedback.

To better assist you with the HDMI port resolution and refresh rate issue after the firmware update, we would like to gather more information.

Please confirm the following:

1. Resolution details: You mentioned "4K/1080p resolution with 25Hz/24Hz/23.98Hz refresh rate, 720p resolution". Could you please provide more specific resolution information? For example, 3840x2160 @ 240Hz, 1920x1080 @ 240Hz.
2. Previous version status: Before the firmware update, could your display support these resolutions and refresh rates?
3. Unable to use: When you set these resolutions and refresh rates, what is the display status? Is there no display at all, or is there an abnormal display?
4. Video recording: If possible, please record a video of the issue occurring. This will help us better understand the problem. Please use MP4 format.
5. Factory reset: We recommend that you reset the display to its factory settings and reconfigure the resolution and refresh rate to see if the issue persists.

Thank you.

[MA77HIAS]

Thanks, again, for taking the time to help out! It is very much appreciated.

1. 3840x2160 @ 25Hz/24Hz/23.98Hz, 1920 x 1080 @ 25Hz/24Hz/23.98Hz, 1280 x 720 @60Hz/50Hz/... (it doesn't work at all anymore)
2. Absolutely. This is very important to me, so it was one of the first things I checked when I bought the device and after the update to MCM103 as well. I use it daily, so I immediately notice it when it is broken. It worked just fine with MCM101 (the firmware the device came with) and MCM103.
3. The display goes black, just like when it normally switches resolution and/or refresh rate. But as long as the broken resolution is set by the system (console, streaming box), the image never returns and the display stays black. There is no abnormal display of anything. Just black. The device does not enter stand-by or signal any error. The power led stays red, as it is normal. Once the system (console, streaming box) sets a working resolution / refresh rate, the display returns. While it is in this state, all device buttons (menu, power, ...) no longer work.
4. If I could kindly ask that we forgo the video recording, that would be quite nice. There is really nothing to see except for a pitch black screen (see point 3) and the red power led.
5. Just to be absolutely certain, I did a third factory reset this morning but the issue persists.

I did further tests:

• VRR on/off makes no difference.
• HDMI CEC on/off makes no difference too (I really would have been surprised if it did).

Also, it does not matter if an app like Netflix initiates the resolution / refresh rate switch or if I manually cycle through the various resolution / refresh rates through the system settings. And this happens regardless of the connected system (Google TV Streamer, NVIDIA Shield Pro (2019), ...).

[Aureliannn_ROG]

Hi @MA77HIAS ,

We would like to confirm a few details. 

When the black screen occurs, does the background sound continue to play, or is there no signal and sound output at all?

You mentioned that "regardless of the connected system (Google TV Streamer, NVIDIA Shield Pro (2019), ...), this situation occurs." 

Does this mean that the issue happens when the monitor is connected to any of these devices? If you use another monitor, does it display normally?

Please help us confirm these questions.

We greatly appreciate your understanding and cooperation.

Thank you.

[MA77HIAS]

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When the black screen occurs, does the background sound continue to play, or is there no signal and sound output at all?

I do not use the speakers of the PG32UDCP but yes, the audio continues indefinitely on the AV-Receiver without any hiccups, so the video seems to be running without a problem-- just without any picture on the monitor.

---

Does this mean that the issue happens when the monitor is connected to any of these devices? If you use another monitor, does it display normally?

It works perfectly fine, in the same setup and with the same devices, when connected to an older 4k 27" LG monitor. It also worked just fine with MCM101 and MCM103 with the PG32UDCP on the same day I made the upgrade to MCM106. It was precisely after that upgrade, that it stopped working without any changes (either software or hardware) to the other devices. The culprit in this regard is with 100% certainty the MCM106 firmware, I am affraid.

Thanks, by the way, for following up with me. That is very much appreciated!

Have a nice day,
Matthias

[Aureliannn_ROG]

Hi @MA77HIAS ,

we apologize for the delayed response due to the recent holiday.

Thank you for providing the relevant information. We have already forwarded this issue to our backend team for further investigation. 

Meanwhile, we would like to confirm the following:

1. When the black screen occurs, the display shows no image, but background audio continues playing, and the issue does not resolve itself. Do you need to unplug and reconnect the cables or readjust the resolution for the screen to return to normal?

Additionally, to better understand the situation, please provide your graphics card model and driver version so that we can analyze the issue further. 

Thank you!

[MA77HIAS]

Hello @Aureliannn_ROG ,

Thank you, as always, for still following up on this issue-- it is honestly very much appreciated.

To answer your question: When the issue occurs (that is, when the HDMI connected device switches to a refresh rate and resolution combo that doesn't work anymore), the screen stays black for as long as the refresh rate and  resolution combo is active. As soon as the HDMI connected device switches back to a "working" refresh rate and resolution combo, the image returns. During that black screen phase, the screen neither enters stand-by nor does it show an error nor does the menu work.

Like I stated earlier, the graphics card model and driver version are irrelevant. 80% of the time, the HDMI connected devices are the Google TV Streamer and the NVIDIA Shield Pro (2019)-- both worked absolutely fine before MCM106. But another connected PC (which  incidentially uses HDMI) has a GeForce 2080 TI and currently has driver version 572.16. But again, this is not a driver nor graphics card problem / incompatibility since both the other devices use Android/Google TV and also very different chipsets from each other.

I hope I could answer your questions to your satisfaction.

Please let me know if there is anything else I can do to help.

Have a nice weekend,
Matthias