Caijinglong Posted June 20, 2020 Share Posted June 20, 2020 (edited) My monitor's contrast is locked and cannot be adjusted (the monitor's physical buttons also cannot be adjusted). I have a LG monitor UL550w, which can be used as an external monitor to adjust the contrast on iMac devices, even under Windows. However, when I connect the monitor to the device booted by OpenCore, the contrast cannot be modified. I connect to the DP interface of RX590, and the corresponding interface of the monitor is also DP. The real device I simulated is iMac 19, 1. My OpenCore version is 0.5.9. The device of OpenCore I use are as follows: intel 9400 ASRock Z390 pro4 PowerColor RX590 --- The adjustment window of the monitor, the second item is the contrast, it is be locked. My personal guess may be because the macOS thinks this device is an iMac, and the default display device is a built-in display, and the contrast of the built-in display cannot be adjusted, so the contrast is locked. So, how should I solve this problem? Edited June 20, 2020 by Caijinglong Link to comment https://www.insanelymac.com/forum/topic/344213-how-to-lift-the-limitation-on-the-contrast-of-the-monitor/ Share on other sites More sharing options...
Cyberdevs Posted June 20, 2020 Share Posted June 20, 2020 2 hours ago, Caijinglong said: My monitor's contrast is locked and cannot be adjusted (the monitor's physical buttons also cannot be adjusted). So, how should I solve this problem? No it has nothing to do with the iMac19,1 SMBIOS and macOS, it's the monitor itself because it is using a predefined settings. Go to Display's Settings (like in the picture) and go to "Picture" then select the "Picture Mode" to Custom(Game) and then inside the "Picture Adjust" you can adjust Brightness, Contrast and the Sharpness. Cheers Link to comment https://www.insanelymac.com/forum/topic/344213-how-to-lift-the-limitation-on-the-contrast-of-the-monitor/#findComment-2726124 Share on other sites More sharing options...
Caijinglong Posted June 20, 2020 Author Share Posted June 20, 2020 I tried all modes (including custom), and the contrast is gray and not adjustable. So, I don't know where is the problem. And, I try use an application: MonitorControl, the contrast isn't adjustable. The sound volume and brightness are adjustable. Link to comment https://www.insanelymac.com/forum/topic/344213-how-to-lift-the-limitation-on-the-contrast-of-the-monitor/#findComment-2726125 Share on other sites More sharing options...
Cyberdevs Posted June 20, 2020 Share Posted June 20, 2020 try http://gscs-b2c.lge.com/downloadFile?fileId=oUPWP5KHNfrF9pvvVc36lQ it's the display settings manager from LG. Or you can reset the settings of the display to the factory settings and start to reconfigure it afterwards. Link to comment https://www.insanelymac.com/forum/topic/344213-how-to-lift-the-limitation-on-the-contrast-of-the-monitor/#findComment-2726127 Share on other sites More sharing options...
Caijinglong Posted June 20, 2020 Author Share Posted June 20, 2020 Forgot to say, I have also tried to install LG's official control app, and the contrast cannot be adjusted. So I came to ask for help, because there is no way for OpenCore to disguise the display as an external display. Because I didn't find the same problem in OpenCore documentation and google. Link to comment https://www.insanelymac.com/forum/topic/344213-how-to-lift-the-limitation-on-the-contrast-of-the-monitor/#findComment-2726130 Share on other sites More sharing options...
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