Resolution reported incorrectly

[guythomson]

What Happened?

[I think the LG UltraGear 32GP850-B has a quirk in its EDID - it reports its max supported resolution as 3840 2160 resolution despite it actually being a 2560 1440 panel]

On other OSes, they normally come up in 4k with this monitor doing a shoddy job of downscaling. Elementary OS 7 seems to get it right, coming up in 2560 1440, however the Display Settings screen reports it as 3840 2160 at 60Hz.

If I switch to the 2k resolution, nothing happens to the screen but I get the is it ok prompt. Then I can switch to 4k at 60 Hz properly this time, the screen goes black and comes back in all its tiny downscaled glory. Once I'm there, I can successfully switch back to 2560 * 1440 at 144Hz (screen shot of settings attached).

However, when I close and reopen display settings, the screen is showing that my monitor is running at 3840 * 2160 at 60Hz again.

Steps to Reproduce

Open display settings

Expected Behavior

The resolution and refresh rate should be correct

OS Version

Elementary OS 7.0 (Horus)

Software Version

Latest release with all current updates

Log Output

No response

Hardware Info:

Monitor: LG UltraGear 32GP850-B CPU: i5-10210U iGPU: UHD 620

[vjr]

@guythomson Are you able to try this potential fix here? https://github.com/elementary/switchboard-plug-display/pull/337

[guythomson]

I've checked it out and installed it - it's better but it doesn't fix the underlying problem.

• It does fix the issue with the resolution being wrong on first open though, now it displays 2560 * 1440 at 144 Hz when I first open it.
• However if I change to 3840 2160 at 60 Hz, close the settings screen, then reopen it, it goes back to displaying 2560 1440 at 144 Hz even though it clearly (or blurrily in this monitor's case!) isn't (screen shot attached)

[vjr]

OK let me see if I can update the PR over the weekend to better handle resolution changes.

[guythomson]

OK let me see if I can update the PR over the weekend to better handle resolution changes.

Thanks!

[vjr]

@guythomson could you try the latest code from https://github.com/elementary/switchboard-plug-display/pull/337 and let us know how it works for you now?

I have a 4k TV which reports an additional larger resolution 4096x2160 and I believe I have been able to reproduce the issues you described and my latest commit (which works better for me) should improve things for you too.

[guythomson]

That's perfect - using current head of origin/prefer-native-aspect worked like a charm. Great job, thank you @vjr!

[vjr]

Thanks @guythomson for re testing and reporting back, appreciated.