Monitorcontrol: Volume/brightness increments don't work properly on non standard scales

[victorchabbert]

Hello,

When using my monitor over usb-c with the lid closed and a magic keyboard 2, my volume is capped at 4 bars when using the media keys (12/50 in monitor values).
However, when using ⇧ + ⌥ + Volume up/down, I can increase the volume above 4 bars.
Moreover, once this threshold crossed, I cannot increase volume in normal increments; decreasing works fine.

Using the sliders from the menu bars works even though the volume and brightness sections are greyed out.

Greyed out sections in the menubar screenshot

Troubleshooting:

• [x] Restarted macbook
• [x] Restarted monitor
• [x] Ran ddcctl (see below)
• [x] Tried different cables:
  
  
  
  • USB-C to USB-C
  
  
  • HDMI to USB-C
  
  

ddcctl

I compiled ddcctl locally for amd and intel.
Running ./ddcctl -d 1 -v <volume> was successful in changing the volume.
(My monitor volume ranges between 0 and 50)

Information:

| Type | Model/Version |
|-------------------------|-------------------|
| Display | BenQ EX2780q over USB-C |
| Device | MBP 15" (2016) |
| OS | 10.15.4 |
| Monitor Control | 2.0.0 (Build 640) |

[marosholly]

I have the issue with the same monitor + mac mini 2018

[bottlebug]

I have a similar issue.

At this level, my monitor displays it at 95/100. Any higher and it will go above 100 which doesn't make any sense. Each increment is also not the same value.

[JoniVR]

I wonder if this is a Monitor specific issue or a problem with MonitorControl 🤔

Each increment is also not the same value.

This is a feature, it's done this way because we display the native macOS OSD and otherwise it would end up with uneven chicklet filling or other issues.

[victorchabbert]

Is MonitorControl a wrapper around ddcctl ?

I might take a stab at modifying the app locally to see if I can get something working

[JoniVR]

Not anymore, it's currently using https://github.com/reitermarkus/DDC.swift

[JoniVR]

My best guess is it has something to do with the way we currently calculate volume steps and the fact that your monitor maxes out at 50, but I'm not sure.

[victorchabbert]

Hum I see. Would it be realistic to add an option to specify the upper cap ?
I could try to verify this theory by changing the cap if need

[JoniVR]

Yes, either we take a look at the calculation method again or provide the ability to define a custom bounds. I think the custom bounds is probably the best approach as every single monitor seems to do something different.. lol.

[victorchabbert]

After compiling and running locally, I got this at startup:

startup logs

2020-06-10 21:50:29.946110+0200 MonitorControl[57013:921861] [plugin] AddInstanceForFactory: No factory registered for id <REMOVED>
2020-06-10 21:50:29.985942+0200 MonitorControl[57013:921861]  HALC_ShellDriverPlugIn::Open: Can't get a pointer to the Open routine
2020-06-10 21:50:29.986665+0200 MonitorControl[57013:921861]  HALC_ShellDriverPlugIn::Open: Can't get a pointer to the Open routine
2020-06-10 21:50:30.013714+0200 MonitorControl[57013:921861]  HALC_ShellDriverPlugIn::Open: Can't get a pointer to the Open routine
Event tap creation failed: is your application sandboxed?
2020-06-10 21:50:30.129573+0200 MonitorControl[57013:921861] Metal API Validation Enabled
2020-06-10 21:50:30.288786+0200 MonitorControl[57013:922421] flock failed to lock maps file: errno = 35
2020-06-10 21:50:30.324510+0200 MonitorControl[57013:922421] flock failed to lock maps file: errno = 35
2020-06-10 21:51:03.083698+0200 MonitorControl[57013:921861] Service port vendor ID 0 differs from display product ID 2513.
2020-06-10 21:51:03.085799+0200 MonitorControl[57013:921861] Framebuffer: AMDFramebufferVIB
2020-06-10 21:51:03.085842+0200 MonitorControl[57013:921861] Location: IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/PEG0@1/IOPP/GFX0@0/ATY,Berbice@1/AMDFramebufferVIB/display0/AppleDisplay
2020-06-10 21:51:03.085870+0200 MonitorControl[57013:921861] Vendor ID: 2513, Product ID: 32630, Serial Number: 21573
2020-06-10 21:51:03.085888+0200 MonitorControl[57013:921861] Unit Number: 7
2020-06-10 21:51:03.085898+0200 MonitorControl[57013:921861] Service Port: 57363
2020-06-10 21:51:03.086551+0200 MonitorControl[57013:921861] kIOI2CSimpleTransactionType is supported.
2020-06-10 21:51:03.086786+0200 MonitorControl[57013:921861] Supported display found: BenQ EX2780Q (Vendor: 2513, Model: 32630)
2020-06-10 21:51:03.094209+0200 MonitorControl[57013:921861] Polling 10 times
2020-06-10 21:51:03.098524+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.098657+0200 MonitorControl[57013:921861] Response was: 00 00 00
2020-06-10 21:51:03.098675+0200 MonitorControl[57013:921861] Display does not support DDC.
2020-06-10 21:51:03.154646+0200 MonitorControl[57013:921861] Display supports enabling DDC application report.
2020-06-10 21:51:03.212942+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.213110+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.261382+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.261496+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.308299+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.308423+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.355068+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 228.
2020-06-10 21:51:03.355188+0200 MonitorControl[57013:921861] Response was: 62 00 00 32 00 0C E8 00 00 00 00
2020-06-10 21:51:03.403766+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.403903+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.452596+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.452711+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.501163+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.501327+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.549436+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.549597+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.598476+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.598588+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.646532+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.646646+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.646724+0200 MonitorControl[57013:921861] Reading 98 failed.
2020-06-10 21:51:03.647429+0200 MonitorControl[57013:921861] BenQ EX2780Q (DDC.DDC.Command.audioSpeakerVolume):
2020-06-10 21:51:03.647453+0200 MonitorControl[57013:921861]  - current ddc value: 12 - from display? false
2020-06-10 21:51:03.647465+0200 MonitorControl[57013:921861]  - maximum ddc value: 50 - from display? false
2020-06-10 21:51:03.647478+0200 MonitorControl[57013:921861] Polling 10 times
2020-06-10 21:51:03.647493+0200 MonitorControl[57013:921861] BenQ EX2780Q (DDC.DDC.Command.audioMuteScreenBlank):
2020-06-10 21:51:03.695152+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 50.
2020-06-10 21:51:03.695254+0200 MonitorControl[57013:921861] Response was: 00 62 00
2020-06-10 21:51:03.695271+0200 MonitorControl[57013:921861] Display does not support DDC.
2020-06-10 21:51:03.751723+0200 MonitorControl[57013:921861] Display supports enabling DDC application report.
2020-06-10 21:51:03.809028+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.809205+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.857687+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.857808+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.906231+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.906350+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:03.954414+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:03.954534+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.003777+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.003937+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.052573+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.052688+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.098695+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.098812+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.147349+0200 MonitorControl[57013:921861] Reading 141 took 8 tries.
2020-06-10 21:51:04.147389+0200 MonitorControl[57013:921861]  - current ddc value: 2
2020-06-10 21:51:04.147399+0200 MonitorControl[57013:921861]  - maximum ddc value: 2
2020-06-10 21:51:04.151176+0200 MonitorControl[57013:921861] Polling 10 times
2020-06-10 21:51:04.195240+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.195378+0200 MonitorControl[57013:921861] Response was: 00 00 00
2020-06-10 21:51:04.195405+0200 MonitorControl[57013:921861] Display does not support DDC.
2020-06-10 21:51:04.251659+0200 MonitorControl[57013:921861] Display supports enabling DDC application report.
2020-06-10 21:51:04.308853+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.308974+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.356833+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.356960+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.403957+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.404078+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.452576+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 228.
2020-06-10 21:51:04.452691+0200 MonitorControl[57013:921861] Response was: 10 00 00 64 00 12 D2 00 00 00 00
2020-06-10 21:51:04.498163+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.498275+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.546428+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.546540+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.594234+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.594347+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.641869+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.641988+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.689950+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 228.
2020-06-10 21:51:04.690078+0200 MonitorControl[57013:921861] Response was: 10 00 00 64 00 12 D2 00 00 00 00
2020-06-10 21:51:04.738796+0200 MonitorControl[57013:921861] Checksum of reply does not match. Expected 0, got 80.
2020-06-10 21:51:04.738935+0200 MonitorControl[57013:921861] Response was: 00 00 00 00 00 00 00 00 00 00 00
2020-06-10 21:51:04.738959+0200 MonitorControl[57013:921861] Reading 16 failed.
2020-06-10 21:51:04.739082+0200 MonitorControl[57013:921861] BenQ EX2780Q (DDC.DDC.Command.luminance):
2020-06-10 21:51:04.739099+0200 MonitorControl[57013:921861]  - current ddc value: 18 - from display? false
2020-06-10 21:51:04.739112+0200 MonitorControl[57013:921861]  - maximum ddc value: 100 - from display? false

Does it help triaging the issue ?

I will investigate further at some other time.