[GH-ISSUE #335] LG 38GL950G has partial range support, highest volume mutes #266

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opened 2026-05-05 05:38:51 -06:00 by gitea-mirror · 3 comments

gitea-mirror commented

2026-05-05 05:38:51 -06:00

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Originally created by @Hexxeh on GitHub (Nov 26, 2020).
Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/335

Originally assigned to: @waydabber on GitHub.

Checklist

I have searched for existing issues
I have looked through the Monitor Troubleshooting wiki
I have updated MonitorControl to the latest version

Describe the issue
LG 38GL950G connected via USB-C to HDMI adaptor to 2019 Macbook Pro 15" can control volume and brightness, but has several quirks

Volume settings behave incorrectly at both ends of the scale:

OSD shows 5/100 at level 1 brightness on OSX overlay, but goes to 25/100 at level 0 on OSX overlay
Highest volume setting on OSX overlay turns off sound completely I: VCP control #98 (0x62) = current: 255, max: 255

Brightness settings behave incorrectly for much of the scale:

OSD turns off entirely and doesn't show changes made by OSX, just shows / character when brightness set by OSX
OSX overlay brightness levels 0-4 show no change in brightness. I: VCP control #16 (0x10) = current: 60, max: 194 values stick at 60 even when settings change lower than 4.
Highest OSX overlay brightness setting is approximately 50% of the monitors max brightness. I: VCP control #16 (0x10) = current: 194, max: 194

Not sure if these are just quirks of my monitor that can't be fixed, since in some cases the range reports correctly. If so, maybe I can help implement quirks support to handle these?

Expected behavior
Brightness and volume control same full range possible via OSD.

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Add any other context about the problem here.

Environment Information (please complete the following information):

macOS version: 10.15.7
MonitorControl version: 2.1.0 Build 721
Monitor(s): LG 38GL950G
Mac model: Macbook Pro 15" Late 2019
Monitor Cable(s)/Connection(s): HDMI via USB-C

Originally created by @Hexxeh on GitHub (Nov 26, 2020). Original GitHub issue: https://github.com/MonitorControl/MonitorControl/issues/335 Originally assigned to: @waydabber on GitHub. **Checklist**  - [x] I have searched for existing issues - [x] I have looked through [the Monitor Troubleshooting wiki](https://github.com/MonitorControl/MonitorControl/wiki/Monitor-Troubleshooting) - [x] I have updated MonitorControl to the latest version **Describe the issue** LG 38GL950G connected via USB-C to HDMI adaptor to 2019 Macbook Pro 15" can control volume and brightness, but has several quirks Volume settings behave incorrectly at both ends of the scale: - OSD shows 5/100 at level 1 brightness on OSX overlay, but goes to 25/100 at level 0 on OSX overlay - Highest volume setting on OSX overlay turns off sound completely `I: VCP control #98 (0x62) = current: 255, max: 255` Brightness settings behave incorrectly for much of the scale: - OSD turns off entirely and doesn't show changes made by OSX, just shows `/` character when brightness set by OSX - OSX overlay brightness levels 0-4 show no change in brightness. `I: VCP control #16 (0x10) = current: 60, max: 194` values stick at 60 even when settings change lower than 4. - Highest OSX overlay brightness setting is approximately 50% of the monitors max brightness. `I: VCP control #16 (0x10) = current: 194, max: 194` Not sure if these are just quirks of my monitor that can't be fixed, since in some cases the range reports correctly. If so, maybe I can help implement quirks support to handle these? **Expected behavior** Brightness and volume control same full range possible via OSD. **Screenshots** If applicable, add screenshots to help explain your problem. **Additional context** Add any other context about the problem here. **Environment Information (please complete the following information):** - macOS version: 10.15.7 - MonitorControl version: 2.1.0 Build 721 - Monitor(s): LG 38GL950G - Mac model: Macbook Pro 15" Late 2019 - Monitor Cable(s)/Connection(s): HDMI via USB-C

gitea-mirror

2026-05-05 05:38:51 -06:00

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gitea-mirror commented

2026-05-05 05:38:55 -06:00

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@Hexxeh commented on GitHub (Nov 27, 2020):

Noticed for brightness that setting /ddcctl -d 1 -b 255 does result in a brighter image than full brightness via MonitorControl, which I'm guessing is stopping at the reported 194 max.

@Hexxeh commented on GitHub (Nov 27, 2020): Noticed for brightness that setting `/ddcctl -d 1 -b 255` does result in a brighter image than full brightness via MonitorControl, which I'm guessing is stopping at the reported 194 max.

gitea-mirror commented

2026-05-05 05:38:58 -06:00

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@waydabber commented on GitHub (Aug 19, 2021):

It would be great to have an advanced preferences option where DDC min. and max. values could be overridden. I will assign this task to myself, but I don't know when will I be able to actually implement it. :)

@waydabber commented on GitHub (Aug 19, 2021): It would be great to have an advanced preferences option where DDC min. and max. values could be overridden. I will assign this task to myself, but I don't know when will I be able to actually implement it. :)

gitea-mirror commented

2026-05-05 05:39:01 -06:00

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Owner

@waydabber commented on GitHub (Aug 19, 2021):

Hi, since this is a duplicate of the issue below, I'll close this issue now - please follow developments here:

https://github.com/MonitorControl/MonitorControl/issues/310

@waydabber commented on GitHub (Aug 19, 2021): Hi, since this is a duplicate of the issue below, I'll close this issue now - please follow developments here: https://github.com/MonitorControl/MonitorControl/issues/310