Adding/Using HiDPI custom resolutions

[bluepr0]

Okay so this was getting pretty ridiculous pretty fast. I'm have no idea what happened but when I reinstalled macOS Mojave on top of my existing disk (without erasing its contents) I lost the 4k output and was not able to get it back. The monitor won't go beyond those 2560x1440.

What I just did was to restore my backup which was working fine and I got it working back again. I'm going to attach the files again but it's already evident that the clock changed.

The only difference is that I was using the 4.9.1a4 beta version but yesterday when I deleted and re-installed SwitchResX the beta was gone as it's now released as 4.9.1. Or either I'm doing something wrong (most probably) or some weird stuff is going on with this release

This is a total mystery for me!. As always, thanks a lot for all your help @joevt. I really can't thank you enough, you are awesome!

 

[joevt]

Okay so this was getting pretty ridiculous pretty fast. I'm have no idea what happened but when I reinstalled macOS Mojave on top of my existing disk (without erasing its contents) I lost the 4k output and was not able to get it back. The monitor won't go beyond those 2560x1440.

What I just did was to restore my backup which was working fine and I got it working back again. I'm going to attach the files again but it's already evident that the clock changed.

The only difference is that I was using the 4.9.1a4 beta version but yesterday when I deleted and re-installed SwitchResX the beta was gone as it's now released as 4.9.1. Or either I'm doing something wrong (most probably) or some weird stuff is going on with this release

This is a total mystery for me!. As always, thanks a lot for all your help @joevt. I really can't thank you enough, you are awesome!

Looks like everything is working AGDCDiagnose output shows 4 lanes of DisplayPort 1.2 as expected and the timing is now 4K60 (533 MHz) in your screenshot. I guess the 320 MHz pixel clock frequency max doesn't matter in this case.

 

[bluepr0]

Looks like everything is working AGDCDiagnose output shows 4 lanes of DisplayPort 1.2 as expected and the timing is now 4K60 (533 MHz) in your screenshot. I guess the 320 MHz pixel clock frequency max doesn't matter in this case.

Yeah when restored the backup everything started to work again as previously.

What I wonder is what was wrong in the files that was making the display connection work at such low res and clocks. Do you have any ideas?

Super weird that I had to Restore the backup and was unable to make it work :/

 

[joevt]

What I wonder is what was wrong in the files that was making the display connection work at such low res and clocks. Do you have any ideas?

Super weird that I had to Restore the backup and was unable to make it work :/

No idea. Super weird is too weird for me.

 

[vrudikov]

Hi, all! Is it possible to use this approach on Hackintosh with single monitor? Monitor is Lenovo L24q-10. 2.560 x 1.440

P.S.: found the answer here

 

[joevt]

Hi, all! Is it possible to use this approach on Hackintosh with single monitor? Monitor is Lenovo L24q-10. 2.560 x 1.440

P.S.: found the answer here

Hackintosh or not doesn't matter. As for your display size, my 2560x1600 display has HiDPI modes enabled so it should work for you. I have HiDPI modes from 720x450 up to 4096x2048 (connected using Nvidia GTX 680 which has a max frame buffer size of 8192x4096; macOS Catalina). Apple might limit the max frame buffer size of an iGPU display to 6720 x 3780 (seems to be the case with the Intel UHD Graphics 630 of my Mac mini 2018 - I haven't checked the older i7-6700K recently).

 

[vrudikov]

As I read from the topic I mentioned:

If you scale 2560x1440 to 1920x1080, your display will try to show 1 visible pixel with 1.5 physical pixels. So the picture will be blurry in the result.

You have three options:

1. Work in native 2K resolution. Sharp image, but UI could be smaller than usual if your screen size is less then 27 inches.
2. Get HiDPI with 1280x720. Sharp but pixelated image (big screen, low resolution), super big UI.
3. Scale your image to 1920x1080. Bigger UI size, but blurry image.

No magic. You can't trick a pixel grid.

So as I understand it doesn't make any sense to try?

It works as designed on macbook - the same 2.560 x 1.440, but Macbook has 15inch screen

 

[joevt]

As I read from the topic I mentioned:

So as I understand it doesn't make any sense to try?

A 1920x1080 HiDPI resolution drawn on a 2560x1440 resolution screen means 2.25 frame buffer pixels per physical pixel. But that doesn't mean it's useless. You're still getting 3840x2160 pixels worth of information but some of that information has to be combined from multiple pixel into a single pixel. Consider it like multi-sampling or bilinear interpolation, etc.

Point #1: 2560x1440 native resolution: Sharp image. Small UI for displays smaller than 27 inches.

Point #2 is inaccurate. It's more like "Get HiDPI with 1280x720. Sharp image. Big UI (4 times as big as native)". The resolution is the same as your display 2560x1440.

Point #3 1920x1080 timing (scaled by display) or scaled resolution (scaled by GPU): UI is not as big as #2 (2.25 times as big as native). The different scalers may give different results. For example, the scaler in my Apple 30" Cinema Display scales 1280x800 to 2560x1600 by using the same pixel four times which might be too sharp. The scaler of the graphics card adds some interpolation (smoothing or blurring).

In a later post, someone wanted 125% scaling:

For a 125% scaling (1.25 as big as native resolution):
2560*1440/1.25=2949120=16a*9a
a=√(2949120/(16*9))=143.10≈143
a*16=2288
a*9=1287
= 2288x1287 HiDPI = 4576x2574

If they mean for each dimension to be scaled by 1.25 times, then that's 1.25*1.25=1.5625 as big as native resolution.
2560*1440/1.5625=2359296
a=128
2048x1152 HiDPI = 4096x2304

I did that the hard way. The easy way is to just use 1.25 for each dimension:
or 2560/1.25x1440/1.25=2048x1152

And in the previous calculation, I could have just used √1.25= for each dimension:
2560/√1.25x1440/√1.25=2290x1288
but then it's more work to get an exact 16:9 resolution (2288x1287)

 

[vrudikov]

A 1920x1080 HiDPI resolution drawn on a 2560x1440 resolution screen means 2.25 frame buffer pixels per physical pixel. But that doesn't mean it's useless. You're still getting 3840x2160 pixels worth of information but some of that information has to be combined from multiple pixel into a single pixel. Consider it like multi-sampling or bilinear interpolation, etc.

Point #1: 2560x1440 native resolution: Sharp image. Small UI for displays smaller than 27 inches.

Point #2 is inaccurate. It's more like "Get HiDPI with 1280x720. Sharp image. Big UI (4 times as big as native)". The resolution is the same as your display 2560x1440.

Point #3 1920x1080 timing (scaled by display) or scaled resolution (scaled by GPU): UI is not as big as #2 (2.25 times as big as native). The different scalers may give different results. For example, the scaler in my Apple 30" Cinema Display scales 1280x800 to 2560x1600 by using the same pixel four times which might be too sharp. The scaler of the graphics card adds some interpolation (smoothing or blurring).

In a later post, someone wanted 125% scaling:

For a 125% scaling (1.25 as big as native resolution):
2560*1440/1.25=2949120=16a*9a
a=√(2949120/(16*9))=143.10≈143
a*16=2288
a*9=1287
= 2288x1287 HiDPI = 4576x2574

If they mean for each dimension to be scaled by 1.25 times, then that's 1.25*1.25=1.5625 as big as native resolution.
2560*1440/1.5625=2359296
a=128
2048x1152 HiDPI = 4096x2304

I did that the hard way. The easy way is to just use 1.25 for each dimension:
or 2560/1.25x1440/1.25=2048x1152

And in the previous calculation, I could have just used √1.25= for each dimension:
2560/√1.25x1440/√1.25=2290x1288
but then it's more work to get an exact 16:9 resolution (2288x1287)

Okay. Cool. So it's possible...

P.S.: @joevt I think you have a degree in math

 

[vrudikov]

@joevt Well I don't know what is that but I created a custom resolution in SwitchResX and I successfully switched to 4k res. Is that kinda upscale or what?

Maybe if this monitor can handle 4k res I can do 1080p HiDPI?