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Add a simple setting in Intel Arc Control for native resolution output

Matthias_Saigon
711 Views

This has been a problem for years. I still don't understand the rationale behind it, but here we go:

 

You can select a resolution of 1280x720 for your second display connected to your integrated Intel UHD Graphics 730. And we need this 720p resolution for our HDMI-SDI switch and the Roland mixer behind it. But the Roland mixer shows an error message. Why?

 

If you go (in Windows 10) to Display > Advanced display settings > Choose display you see under Display information the "Desktop resolution 1280x720" but below as "Active signal resolution 1920x1080". Which is not a 720p signal our Roland mixer is expecting, when I change the resolution in Windows to 720p.

 

In the old Intel Graphics Control Center there was a setting called "Maintain Display Scaling" but this setting does not exist in the new Intel Arc Control:

 

April_2022.jpg

As you can see, there is a "scale" option, and you can select "Maintain Display Scaling". Which means that, if you select a 720p signal output, you get a 720p signal output. Currently I'm working for over an hour already, and can't find a solution that worked in April 2022 with the old driver. It would be great to get this setting back! I don't need a 1080p signal that has a 720p signal somehow embedded. Maybe someone thinks that the upscaler of the graphics is better than in my monitor, but please let me do this decision. Please let me have a720p output when I select one.

 

One final little request: Please refrain from answering to this question in a manner of "Hello, welcome to our forum ... I'm here to help ... have you submitted this request with our special software ... please install this and then ask your question there ... can you give me the version of your driver ... have you updated your driver ... have you updated Windows? ... can you check the HDMI cable ... have you tried switching it on and off again ... please submit a log file" or whatever. If you don't understand the problem, requesting all these information does not help you to understand it better. If you do - you would not ask these questions.

 

In January 2024 the option was still available: https://www.intel.com/content/www/us/en/support/articles/000057700/graphics.html 

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10 Replies
MUC
Valued Contributor III
664 Views

I have also encountered discrepancies between "Desktop resolution" and "Active signal resolution" that I could not explain. Often, this could be resolved by:

 

  • Select Start > Settings > System > Display
  • There’s a link labeled Advanced display settings. This takes you to a second page where you can view the attributes for each monitor. At the top is a drop-down menu listing your displays. Choose the one you want to check if you are using more than one display. Then you can see "Desktop Mode/Resolution" and "Active Signal Mode/Resolution". If they differ proceed as follows:
    • Click the Display adapter properties link.
    • The system will open a window with your GPU properties from the classic Control Panel. Click the List All Modes button.
    • Select desired resolution in the next dialog. Note that Windows lists a single resolution several times with different refresh rates. Make sure you pick the right one.
    • Click OK to save your changes.
    • Click OK to leave the property window.

      NOTE: If changes don’t take effect, then it may be useful to repeat the steps above using another resolution and then again repeat the steps reverting back to your desired one to “synchronize” the Desktop Mode with the Active Signal Mode.

 

Video and graphics issues can basically have their cause in any component of the entire system. It is a network. To investigate those problems, it is usually necessary to prepare all available information in order to enable Tech Support to reproduce the problem. Only then is it possible to permanently fix a defect. We can support the Intel graphics team with the following information:

 

  1. Which driver version last worked perfectly according to your requirements? Please provide the exact version number.

  2. Which source device is being used? Manufacturer and model? Unfortunately, specifying "UHD730" is not enough, as the behavior of an HDMI connection also depends on the technology used by the Original Equipment Manufacturer (OEM) who assembled the device. Motherboard design (signaling path) and physical connectors may have influence. For example, there have been several cases where users of a Dell Inspiron 3501 expected that 4K @ 60 Hz would work via HDMI because that is correctly listed in the technical data for the Intel Tiger Lake platform. Unfortunately, when implementing the processor, Dell decided to limit the physical HDMI port to 1920 x 1080 @ 60 Hz. The OEM always has the final say.

  3. Which switch is being used here? From your screenshot, I can see that the device is reporting in the Extended Display Identification Data (EDID) over the HDMI cable via Display Data Channel (DDC) that this is a BlackmagicDesign (BMD) product. Is that correct?

     
    MUC_1-1736953674836.png

     

     

  4. Which HDMI cable do you use? Manufacturer, model and length?

  5. To analyze the EDID that the PC receives, please create a Report for Intel Graphics Drivers on the PC and attach the output file here.

  6. Roland Corporation makes a variety of audio/video mixing devices. Which one are you using? It appears to have a Serial Digital Interface (SDI) input. Is the monitor also integrated here or are you using another monitor that is embedded in this signal chain elsewhere? Please describe the signal chain in all details, preferably with a sketch.

Matthias_Saigon
358 Views

Hi MUC,

 

thanks for your detailed reply, including well documented steps! I just came here to this forum to add the first steps you describe: Get to List all Modes and select the fitting one. It was a proposed solution I found in many other forums in hours of searching and testing. Your description is so much better than mine would have been, thank you!

And I wanted to add that it does not work and does not change the "Active Signal Mode/Resolution". I switched back to the Intel Arc Control, clicked on Reset to Default, then back to Advanced display settings and changing to the desired mode. At one point both resolutions in "Active Signal Mode/Resolution" and "Desktop Mode/Resolution" aligned to 1280x720 - finally! But the Roland mixer was still not processing the signal. I realized that the refresh rate was set to 60 Hz, but we need 50 Hz (AC frequency here in Vietnam). After switching to 50 Hz the Active Signal Mode switched back to 1920x1080. Wrong Active Signal Mode again ...

It took about 30 minutes to reset, apply, change, back to "List all Modes", select another one, change refresh rate, and confirm that finally the resolution aligned, and the output was 50 Hz. I was able to use the Roland again! 😊 Exactly as MUC wrote above in the Note after the instructions. I was happy! Here a few details:

 

A) The Setup

I think our very specific setup is rarely found, and the problems described here relate only to a few cases. General setups are much simpler and should work in almost all cases (see B later). Here is a simplified signal chain with the cable type in [brackets]:

 

PC: ---[HDMI]--- :Converter HDMI-SDI: ---[SDI]--- :Roland mixer: ---[SDI]--- :Converter SDI-HDMI: ---[HDMI]--- :FullHD TV

 

And MUC is right, the Converter are both from Blackmagic Design, and the picture he used is right, too! This whole chain has 4 cables and 5 elements. All of them are capable of 720p and 1080p with 50Hz and 60 Hz, detect it automatically and work - except the Roland mixer, which only operates at 720p at 50Hz. The Roland mixer has a manual switch on the side to change to 1080i or 1080p, but two camera input signals are 720p 50Hz SDI, so that is the mode we operate in.

The apparent problem or challenge of our setup is that the PC determines its output signal by communicating with the Blackmagic Design converter (as mentioned above by @MUC  over the Extended Display Identification Data (EDID) over the HDMI cable via Display Data Channel (DDC)) and therefore assumes that it can output a 1080p signal without problems. The PC can't see further down the chain, and in most cases this would already be the monitor or TV. For almost all use cases that's the best solution, so the Intel driver defaults to this setting.

 

B) Why the difference in "Desktop resolution" and "Active signal resolution"?

One might ask "Why not just output the selected Desktop solution?". I remember the old CRT monitors where this was the case: The graphics card would send the signal of the selected resolution, and the monitor would adjust its electron beam control unit to produce exactly that resolution. But with current LCDs the displays have only one native resolution, everything else has to be interpolated. There is quite some math and computing power involved to make this nice, and many monitor manufactures don't invest a lot of money into a very good interpolation hardware solution.

Intel's approach to do the interpolation on the GPU and putting it out as Active Signal resolution (assuming that the maximum resolution is also the native resolution) creates therefore a better image in 99% of cases. And it works in 99% of the use cases. As Engineer at Intel I probably would have chosen the same way, it delivers better image quality to the majority of customers.

But there are some special use cases where one would like to change this default setting. The hardware is easily capable of doing it, it "just" has to be implemented in software. And to a degree it has been.

 

C) Intel Graphics Command Center

The screenshot of the original post was taken in April 2022 when we first observed this behavior. It came with a new PC with a i5-12400 CPU, the mainboard is an Asrock ____ (will be updated later). It replaced an old quadcore Haswell (if I remember correctly) that was just using the Desktop resolution as the Active signal resolution, so no problem there. After some time we found the setting "Scale: Maintain Display Scaling" in the IGCC to align desktop and active signal resolution. In May 2024 we installed a new Windows 10 Pro and got it working again after a little tinkering. I'm not completely sure how the Intel Arc Control made it to this PC, since it only has the iGPU of the i5, but it worked until last week. One update changed the Active signal resolution, and the hunt of the seemingly broken Roland started again.

Currently I have a different test system here with a HP Elitedesk 800 TWR G4 i7-8700 (thanks MUC for some background information why just the CPU or GPU might not be sufficient to narrow down possible error sources) running Windows 11 Pro and one monitor connected over DVI, a second one over HDMI. And I discovered that the intel Graphics Command Center still exists and can be downloaded from the Windows store. I currently have version 1.100.5688.0 which is newer than 1.100.2765.0 I referenced in my original post. According to this post on uptodown.com it is from November 11, 2024. And the option "Maintain Display Scaling" is still there! 

Matthias_Saigon_0-1736963592174.png

So I tried 720p on my second display (Samsung LF27T450F FullHD) and got the expected:

Matthias_Saigon_1-1736963737015.png

 

Now switching to "Maintain Display Scaling":

Matthias_Saigon_2-1736963777988.png

What about System > Display > Advanced display and "Display adapter properties for Display 2" followed by "List all modes"? I have 1280x720 with 3 refresh rates available:

Matthias_Saigon_0-1736996194686.png

None changes the Active signal mode. I'll investigate further and will update here. Now just shortly answers to the 6 questions:

 

1. Which driver version last worked perfectly according to your requirements? Please provide the exact version number.

Don't have it currently, I think it is the most recent one. As explained above, I don't think it is relevant, since it is working now with the updated version. I assume it is "only a matter of settings", and with a recent update the settings were changed. The culprit is "only" to get the settings right, all drivers since 2022 were doing a good job creating a native 720p signal as Active signal. As the current driver is doing right now.

 

2. Which source device is being used? Manufacturer and model? Unfortunately, specifying "UHD730" is not enough, as ... The OEM always has the final say.

Thanks again for the detailed explanation! I'll figure out the exact mainboard from ASRock for this i5-12400. Yet I think this is not relevant in our case, since we only use low resolutions like 1080p, and want to go even lower to 720p. Good question nonetheless!

 

3. Which switch is being used here? From your screenshot, I can see that the device is reporting in the Extended Display Identification Data (EDID) over the HDMI cable via Display Data Channel (DDC) that this is a BlackmagicDesign (BMD) product. Is that correct?

Yes it is! Without the 3G, image follows ...

 

4. Which HDMI cable do you use? Manufacturer, model and length?

Cheap no name ones. Less than 1.8 meters, only for 1080p 60Hz. According to my investigation not a source of problems (in this case at least, I had several HDMI cable issues in other projects).

 

5. To analyze the EDID that the PC receives, please create a Report for Intel Graphics Drivers on the PC and attach the output file here.

Done and attached.

 

6. Roland Corporation makes a variety of audio/video mixing devices. Which one are you using? It appears to have a Serial Digital Interface (SDI) input. Is the monitor also integrated here or are you using another monitor that is embedded in this signal chain elsewhere? Please describe the signal chain in all details, preferably with a sketch.

Done partly in A). Specific Roland model follows, it has three SDI inputs and one/two HDMI inputs for a total of 4 channels to switch and blend or PiP. Image follows soon.

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Matthias_Saigon
585 Views

Hi MUC,

 

thanks for your detailed reply, including well documented steps! I just came here to this forum to add the first steps you describe: Get to List all Modes and select the fitting one. It was a proposed solution I found in many other forums in hours of searching and testing. Your description is so much better than mine would have been, thank you!

And I wanted to add that it does not work and does not change the "Active Signal Mode/Resolution". I switched back to the Intel Arc Control, clicked on Reset to Default, then back to Advanced display settings and changing to the desired mode. At one point both resolutions in "Active Signal Mode/Resolution" and "Desktop Mode/Resolution" aligned to 1280x720 - finally! But the Roland mixer was still not processing the signal. I realized that the refresh rate was set to 60 Hz, but we need 50 Hz (AC frequency here in Vietnam). After switching to 50 Hz the Active Signal Mode switched back to 1920x1080. Wrong Active Signal Mode again ...

It took about 30 minutes to reset, apply, change, back to "List all Modes", select another one, change refresh rate, and confirm that finally the resolution aligned, and the output was 50 Hz. I was able to use the Roland again! 😊 Exactly as MUC wrote above in the Note after the instructions. I was happy! Here a few details:

 

A) The Setup

I think our very specific setup is rarely found, and the problems described here relate only to a few cases. General setups are much simpler and should work in almost all cases (see B later). Here is a simplified signal chain with the cable type in [brackets]:

 

PC: ---[HDMI]--- :Converter HDMI-SDI: ---[SDI]--- :Roland mixer: ---[SDI]--- :Converter SDI-HDMI: ---[HDMI]--- :FullHD TV

 

And MUC is right, the Converter are both from Blackmagic Design, and the picture he used is right, too! This whole chain has 4 cables and 5 elements. All of them are capable of 720p and 1080p with 50Hz and 60 Hz, detect it automatically and work - except the Roland mixer, which only operates at 720p at 50Hz. The Roland mixer has a manual switch on the side to change to 1080i or 1080p, but two camera input signals are 720p 50Hz SDI, so that is the mode we operate in.

The apparent problem or challenge of our setup is that the PC determines its output signal by communicating with the Blackmagic Design converter (as mentioned above by @MUC  over the Extended Display Identification Data (EDID) over the HDMI cable via Display Data Channel (DDC)) and therefore assumes that it can output a 1080p signal without problems. The PC can't see further down the chain, and in most cases this would already be the monitor or TV. For almost all use cases that's the best solution, so the Intel driver defaults to this setting.

 

B) Why the difference in "Desktop resolution" and "Active signal resolution"?

One might ask "Why not just output the selected Desktop solution?". I remember the old CRT monitors where this was the case: The graphics card would send the signal of the selected resolution, and the monitor would adjust its electron beam control unit to produce exactly that resolution. But with current LCDs the displays have only one native resolution, everything else has to be interpolated. There is quite some math and computing power involved to make this nice, and many monitor manufactures don't invest a lot of money into a very good interpolation hardware solution.

Intel's approach to do the interpolation on the GPU and putting it out as Active Signal resolution (assuming that the maximum resolution is also the native resolution) creates therefore a better image in 99% of cases. And it works in 99% of the use cases. As Engineer at Intel I probably would have chosen the same way, it delivers better image quality to the majority of customers.

But there are some special use cases where one would like to change this default setting. The hardware is easily capable of doing it, it "just" has to be implemented in software. And to a degree it has been.

 

C) Intel Graphics Command Center

The screenshot of the original post was taken in April 2022 when we first observed this behavior. It came with a new PC with a i5-12400 CPU, the mainboard is an Asrock ____ (will be updated later). It replaced an old quadcore Haswell (if I remember correctly) that was just using the Desktop resolution as the Active signal resolution, so no problem there. After some time we found the setting "Scale: Maintain Display Scaling" in the IGCC to align desktop and active signal resolution. In May 2024 we installed a new Windows 10 Pro and got it working again after a little tinkering. I'm not completely sure how the Intel Arc Control made it to this PC, since it only has the iGPU of the i5, but it worked until last week. One update changed the Active signal resolution, and the hunt of the seemingly broken Roland started again.

Currently I have a different test system here with a HP Elitedesk 800 TWR G4 i7-8700 (thanks MUC for some background information why just the CPU or GPU might not be sufficient to narrow down possible error sources) running Windows 11 Pro and one monitor connected over DVI, a second one over HDMI. And I discovered that the intel Graphics Command Center still exists and can be downloaded from the Windows store. I currently have version 1.100.5688.0 which is newer than 1.100.2765.0 I referenced in my original post. According to this post on uptodown.com it is from November 11, 2024. And the option "Maintain Display Scaling" is still there! 

Matthias_Saigon_0-1736963592174.png

So I tried 720p on my second display (Samsung LF27T450F FullHD) and got the expected:

Matthias_Saigon_1-1736963737015.png

 

Now switching to "Maintain Display Scaling":

Matthias_Saigon_2-1736963777988.png

What about System > Display > Advanced display and "Display adapter properties for Display 2" followed by "List all modes"? I have 1280x720 with 4 refresh rates available:

Matthias_Saigon_3-1736964044686.png

None changes the Active signal mode. I'll investigate further and will update here. Now just shortly answers to the 6 questions:

 

1. Which driver version last worked perfectly according to your requirements? Please provide the exact version number.

Don't have it currently, I think it is the most recent one. As explained above, I don't think it is relevant, since it is working now with the updated version. I assume it is "only a matter of settings", and with a recent update the settings were changed. The culprit is "only" to get the settings right, all drivers since 2022 were doing a good job creating a native 720p signal as Active signal. As the current driver is doing right now.

 

2. Which source device is being used? Manufacturer and model? Unfortunately, specifying "UHD730" is not enough, as ... The OEM always has the final say.

Thanks again for the detailed explanation! I'll figure out the exact mainboard from ASRock for this i5-12400. Yet I think this is not relevant in our case, since we only use low resolutions like 1080p, and want to go even lower to 720p. Good question nonetheless!

 

3. Which switch is being used here? From your screenshot, I can see that the device is reporting in the Extended Display Identification Data (EDID) over the HDMI cable via Display Data Channel (DDC) that this is a BlackmagicDesign (BMD) product. Is that correct?

Yes it is! Without the 3G, image follows ...

 

4. Which HDMI cable do you use? Manufacturer, model and length?

Cheap no name ones. Less than 1.8 meters, only for 1080p 60Hz. According to my investigation not a source of problems (in this case at least, I had several HDMI cable issues in other projects).

 

5. To analyze the EDID that the PC receives, please create a Report for Intel Graphics Drivers on the PC and attach the output file here.

Done and attached.

 

6. Roland Corporation makes a variety of audio/video mixing devices. Which one are you using? It appears to have a Serial Digital Interface (SDI) input. Is the monitor also integrated here or are you using another monitor that is embedded in this signal chain elsewhere? Please describe the signal chain in all details, preferably with a sketch.

Done partly in A). Specific Roland model follows, it has three SDI inputs and one/two HDMI inputs for a total of 4 channels to switch and blend or PiP. Image follows soon.

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Matthias_Saigon
623 Views

The above post was done yesterday evening, and confirmed - but somehow lost on the Intel server. It's partially restored, and some edits were made afterwards, but they await moderator approval. In the meantime I did some further testing:

I switched monitors, cables, ports (DVI and HDMI) on both PC and monitor, and got the same result.

My testing indicates an issue with the driver API, since the hardware is able to generate the native 720p/50 signal and has done so with all drivers since 2022. The different drivers should in general be able to tell the GPU to generate a 720p/50 signal since they have done so since 2022, even after a fresh installation of Windows 10 Pro (from a previous Windows 10 Home or LTSC) and several Intel Arc Control updates. Somehow I got it working yesterday again, but it was more a try-and-error approach. The Intel Arc Control does not have the "Maintain Display Scaling" setting, and in my test setup from yesterday this setting exists in the Intel Graphics Command Center but produces an error and does not work (all other 4 options work as intended).

For comparison I tried a different graphics card manufacturer, and went with a broken Nvidia GTX 1060 (only two DVI ports create an output) on Windows 10 22H2. In standard setting you get the same difference between  "Active Signal Mode/Resolution" and "Desktop Mode/Resolution". But you can use both the NVIDIA Control panel and  the Start > Settings > System > Display > Advanced display settings > Display adapter properties > List All Modes path to change the Active Signal Mode/Resolution. With every single one of them is correctly applied right after pressing the button:

Screenshot 2025-01-16 021711.pngScreenshot 2025-01-16 021605.png

viber_image_2025-01-16_09-31-14-681.jpg

The system has a second GPU, an older GTX 960, connected with just one PCIe lane from a riser card, and limited to PCIe 1.0 speed in the BIOS. And again, with both paths of adjusting it (Nvidia panel and "List all modes") the settings were adjusted to the desired 720p/50. Surprisingly even 4K worked, but that's another topic.

This indicates, as mentioned above, that the problem seems to be how the Intel driver receives the settings from the IGCC or "List all modes" and adjusts its settings. Currently IGCC causes an error, and "List all modes" is ignored in most cases.

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Matthias_Kreier
Beginner
612 Views

Here is just the setup, the longer answer post does not appear here yet:

 

A) The Setup

I think our very specific setup is rarely found, and the problems described here relate only to a few cases. General setups are much simpler and should work in almost all cases (see B later). Here is a simplified signal chain with the cable type in [brackets]:

 

PC: ---[HDMI]--- :Converter HDMI-SDI: ---[SDI]--- :Roland mixer: ---[SDI]--- :Converter SDI-HDMI: ---[HDMI]--- :FullHD TV

 

And MUC is right, the Converter are both from Blackmagic Design, and the picture he used is right, too! This whole chain has 4 cables and 5 elements. All of them are capable of 720p and 1080p with 50Hz and 60 Hz, detect it automatically and work - except the Roland mixer, which only operates at 720p at 50Hz. The Roland mixer has a manual switch on the side to change to 1080i or 1080p, but two camera input signals are 720p 50Hz SDI, so that is the mode we operate in.

The apparent problem or challenge of our setup is that the PC determines its output signal by communicating with the Blackmagic Design converter (as mentioned above by @MUC  over the Extended Display Identification Data (EDID) over the HDMI cable via Display Data Channel (DDC)) and therefore assumes that it can output a 1080p signal without problems. The PC can't see further down the chain, and in most cases this would already be the monitor or TV. For almost all use cases that's the best solution, so the Intel driver defaults to this setting.

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Matthias_Saigon
580 Views

I tried a different PC with a i3-10100 on a ASRock B460M Pro4 with BIOS P1.60 from 07/29/2021 and Windows 11 23H2. The integrated UHD 630 behaves exactly as the UHD 630 on the HP 800 TWR G4 with the i7-8700:

  • The GPU determines the native resolution of the attached device/display by the Extended Display Identification Data (EDID) over the HDMI/DVI cable via Display Data Channel (DDC) and sets that as the "Active Signal Mode/Resolution". Any resolution changes by the user only affect the "Desktop Mode/Resolution" and the GPU interpolates to the higher resolution.
  • Selecting the desired resolution and refresh rate in the Start > Settings > System > Display > Advanced display settings > Display adapter properties > List All Modes selection of the desired mode only affects the Desktop mode, but does not change the Active Signal Mode.
  • Intel Graphics Command Center 1.100.5688.0 Display > Connected Displays > General > Scale > Maintain Display Scaling causes an error (the 4 other options Centered, Streched, Maintain Aspect Ration and Custom work as intended): 

Matthias_Saigon_0-1737050323404.png

My take is that the communication from IGCC or the Windows Advanced Display settings to the driver is broken from the Intel UHD driver side. It worked in 2022, but is currently not working with IGCC. And sometimes it works with the Windows settings (see the Note by @MUC ).

Other graphics card manufactures seems not to have this problem, as the test with Nvidia 960 and 1060 showed. Further testing will follow.

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Matthias_Saigon
579 Views

Generally the path Start > Settings > System > Display > Advanced display settings > Display adapter properties > List All Modes selection should work for all graphics cards in Windows 10 and 11 to adjust the Active Signal Mode to the Desktop mode. Tested systems not working:

  • E3-1226 v3 with HD Graphics P4600/P4700 on Windows 10 22H2 with driver 20.19.15.4531 from 29/09/2016 - while testing on a 1080p display. It worked on a 4K monitor!
  • i5-7300U with HD Graphics 620 and Windows 11
  • i7-8700 with UHD 630
  • i3-10100 with UHD 630 and driver 31.0.101.2125 from 5/24/2023 in Windows 11 23H2
  • i5-12400 with UHD 730 (it finally did with several "reset to default" in the Intel Arc Control and selecting again), Windows 10
  • i7-13700T with UHD 770 in Windows 11 24H2 and driver 32.0.101.6449 from 12/26/2024 (closest to 1280x720 was 1280x800 when selecting 59.81 Hz refresh rate)

Tested systems working right of the box just with 1 click selecting resolution and refresh rate (both Nvidia and AMD):

  • GTX 960 over PCI 1.0 x1
  • GTX 1060 in Windows 10
  • M1000M in zBook 15 G3
  • RTX 3070 Ti in Windows 11
  • RX 470 with Windows 11 24H2

There is a consistency for Intel GPUs since at least the Haswell generation 2014 (tested with the E3-1226 v3) down to UHD 770 in the i7-13700T from 2023 to ignore the setting in Display adapter properties and the selected Mode to apply as Active Signal Mode. At least when connected to a 1080p monitor. 

Exceptions: Testing revealed that hardware from 2014 like the P4600 and the HD 620 from 2016 were accepting the settings and changing the Active Signal Mode when connected to a 4K monitor! Right away, no questions asked. Just with one click. Down to 720p/50 or whatever value you like.

Exception from the exception: This no longer works with 2023 hardware like the UHD 770 connected to a 4K monitor - it stays at 4K and is upscaled.

My takeaway: This seems intentional. Older hardware would be connected in the majority of cases to 1080p monitors. The selection of a mode when connected to a 1080p would just be ignored. There is probably a line in the driver code that checks "if native_resolution == '1920x1080' then select Active_Signal_mode = 1920x1080;". In recent years 4K monitors became more common, so a line for this resolutin was added, which is why 4K on UHD 770 no longer accept other active signal settings.

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MUC
Valued Contributor III
547 Views

The EDID of a sink device is read when connected to the PC and saved in the Windows registry. It can also be changed there (EDID Override).

I can reproduce the described behavior using the EDID of the Samsung LF27T450F from the diagnostic report on my system. The resolution modes are listed multiple times in the EDID, so the EDID seems to be somehow "over-determined". I cannot explain why other graphics drivers can handle this but the Intel drivers obviously have issues here. However, you can influence the behavior with a tool per EDID Override. The easiest way to do this is as follows:

 

  • Download Custom Resolution Utility (CRU)
  • Run CRU.exe
  • Make sure the active EDID is LF27T450F connected to your PC. If necessary, select from the drop down menu (1).


    MUC_0-1737070229653.png

  • Delete the Detailed Timing Descriptor (DTD) above (2). This is no problem since the same resolution and refresh rate with the same timing parameters is also defined within the CTA-861 Extension Block (3).
  • Please close CRU with OK and restart the computer.

 

Note:
All changes made with CRU can be undone if necessary by running "reset-all.exe" from the CRU download package and restarting the system. You can find more information about this tool on the linked page.

 

Now you can change the resolution to 1280 x 720 using the Windows display settings, whereby the active signal mode initially remains as it was. But now you should be able to adjust this using the "List All Modes" method. First set 50 Hz there, for example, and then return to 60 Hz. Now desktop mode and active signal mode should match.

 

MUC_1-1737070812320.png

 

You can play around with the tool as much as you like. Nothing can break. Once done, this procedure maintains active permanently for a specific computer-to-screen combination.

 

To return to the original state, run "reset-all.exe" and restart the device. The original EDID will then be read again via the HDMI cable.

 

Matthias_Saigon
537 Views

Thanks @MUC for this deep dive into the communication between monitor and GPU! This opens a brand new rabbit hole, I just wanted to have the Roland mixer working 😁

 

The solution with the CRU by ToastyX has a long history. The forum post is from 2012, and the copyright info in the source code with the GPL3 also states 2012. Which indicates that similar problems exist for an even longer time to finally motivate a hobbyist to take on the challenge of fixing things.

 

Currently I will probably not touch our settings (never change a running system). But for the next time around I will change the EDID entries for the Blackmagic Design converter, so that 720p/50 is automatically selected. And since I can't edit my older post anymore, here is finally the image: 

bmd.jpg

The BMD converter is just doing it's job, and can easily handle 1080p. But one step further down the chain is the Roland mixer that operates with only one resolution at a time, and we selected 720p with the switch on the right side:

roland.jpg

Another option is to add and use a cheap Nvidia or AMD graphics card. My limited testing with both brands showed that both adjust the Active signal mode/resolution when selecting from the "List all modes". Intel is the outlier.

I'll open a new ticket suggesting to fix the Intel graphics driver. But since the drivers seem to ignore the "List all modes" override for at least 10 years, as my test indicates, there might be a reason why this behavior was chosen and is now the standard for all the million devices using the integrated graphics. While I now understand the reason to have the upscaling to the native resolution being done on the GPU, I can't find a reason why it would be better to ignore the user selection of a resolution/refresh rate from the "List all modes" and stick with the interpolated one. Nvidia and AMD are not doing it. Yet given the large user base Intel might be hesitant to change this "well established" behavior, even if it makes not much sense.

A desirable fix even for Intel would be that the "Maintain Display Scaling" in IGCC starts to work again. As shown above it currently causes an error message in all my test scenarios. It worked in 2022. Another option would be to add a working button like this to the Intel Arc Control. I've seen the push (or popup recommendations) for this software in Windows on PCs with just integrated graphics not from the ARC line. 

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MUC
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To summarize your configuration:

 

MUC_0-1737126072217.png

 

Since the Serial Digital Interface (SDI) works without EDID to transmit video data, the questionable behavior of the Intel drivers only depends on what happens in the top right area, i.e. what EDID the graphics driver receives and how it processes it. Based on the countless PCs you have tested and what I saw yesterday during my EDID testing, I share your conclusions.

 

When processing the created ticket, the Intel graphics team should investigate why the "Maintain Display Scaling" option does not work and the GPU forces scaling in any case when 1080p is advertised as the native mode via EDID. This does not seem to be the case with 4K. I can also confirm this observation. An option as summarized in the thread title would actually help here to set the active signal mode correctly.

 

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