# MWorks always uses main display

**URL:** <https://mworks.discourse.group/t/mworks-always-uses-main-display/97>\
**Category:** Support\
**Tags:** unsolved-mystery\
**Created:** [October 14, 2021, 1:52pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97 "2021-10-14T13:52:12Z")\
**Posts on this page:** 14\
**Page:** 1

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 14, 2021, 1:52pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/1 "2021-10-14T13:52:12Z")

</div>

Selection of either the Main Display or Display 2 results in the display on the Main Display (the one with the macOS Dock).

When these preferences are toggled, they are updated in the user-level file (0 for Main, 1 for Display 2), but the display used does not change, and nor does the system-level file.

Lindsey.

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 14, 2021, 2:04pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/2 "2021-10-14T14:04:06Z")

</div>

Hi Lindsey,

(I split this in to its own discussion.)

Since it sounds like the preferences mechanism is working correctly, we need to start considering other possible causes. Some questions:

1. Are you seeing this issue on multiple Mac’s or just one?
2. Have you made any recent changes to the system(s) where you’ve observed this problem? Did you, for example
  - install a new version of MWorks?
  - upgrade to a newer version of macOS?
  - replace or reconnect either of the displays?

Thanks,  
Chris

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 14, 2021, 6:05pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/3 "2021-10-14T18:05:38Z")

</div>

Hi Chris,  
This issue was just on a single Mac.  
It followed an upgrade from High Sierra to Catalina. We did not install a  
new version of Mworks (though we later tried reinstalling to see if it  
would help- it didn’t) or replace/reconnect the displays (I’m not sure if  
this was ever tried).  
Lindsey.

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 15, 2021, 6:09pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/4 "2021-10-15T18:09:03Z")

</div>

Hi Lindsey,

> It followed an upgrade from High Sierra to Catalina. We did not install a new version of Mworks

OK, that’s useful info. What version of MWorks are you using on that machine?

Chris

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 16, 2021, 1:19am UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/5 "2021-10-16T01:19:45Z")

</div>

MWorks was 0.10 (a nightly). Same as on the other computers.  
Lindsey.

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 20, 2021, 1:58pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/6 "2021-10-20T13:58:35Z")

</div>

Hi Lindsey,

I created a little command-line utility that prints out some info about all the connected displays. I’m hoping it will shed some light on what’s happening here.

You can download the tool [from Dropbox](https://www.dropbox.com/s/tpe93l2dkmtpko3/screeninfo.zip?dl=1). After unzipping it, run it from Terminal. For example, here’s what happens when I run it on my iMac:

```auto
$ ./screeninfo
Screen 0:
    Name: Built-in Retina Display
    Direct Display ID: 1
    Frame: {{0, 0}, {1920, 1080}}
    Vendor number: 0x610
    Model number: 0xA04C
    Serial number: 0xFD626D62
    Is main display? Yes
    Is active? Yes
    Is in mirror set? No
Screen 1:
    Name: LED Cinema Display
    Direct Display ID: 2
    Frame: {{-1920, -120}, {1920, 1200}}
    Vendor number: 0x610
    Model number: 0x9236
    Serial number: 0x274680D
    Is main display? No
    Is active? Yes
    Is in mirror set? No

```

Can you run this on your problematic machine and send me the output?

Thanks,  
Chris

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 20, 2021, 2:17pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/7 "2021-10-20T14:17:40Z")

</div>

Hi Chris,  
Here’s the output:

```auto
Screen 0:
    Name: DELL D2015H
    Direct Display ID: 725364104
    Frame: {{0, 0}, {1920, 1080}}
    Vendor number: 0x10AC
    Model number: 0xF063
    Serial number: 0x41333549
    Is main display? Yes
    Is active? Yes
    Is in mirror set? No
Screen 1:
    Name: DELL 2009W
    Direct Display ID: 722492366
    Frame: {{1920, 30}, {1680, 1050}}
    Vendor number: 0x10AC
    Model number: 0x4042
    Serial number: 0x414E4B4C
    Is main display? No
    Is active? Yes
    Is in mirror set? No

```

Also- I can’t test the other issue with dac\_cycle until we solve this one because it’s the same computer…

Lindsey.

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 20, 2021, 3:50pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/8 "2021-10-20T15:50:32Z")

</div>

Hi Lindsey,

> Here’s the output:

Thanks. Unfortunately, that all looks perfectly reasonable, so it doesn’t really help us.

> Also- I can’t test the other issue with dac\_cycle until we solve this one because it’s the same computer…

I don’t understand. dac\_cycle just runs in Terminal. How does the display issue affect it?

However, it’s interesting that the same machine is exhibiting both of these weird issues. Is this a Mac mini? Is it using an external GPU?

If you don’t mind, could you run the following command in Terminal on that machine and send me the output?

```
/usr/sbin/system_profiler -detailLevel mini SPHardwareDataType SPDisplaysDataType SPUSBDataType

```

Thanks,  
Chris

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 20, 2021, 4:00pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/9 "2021-10-20T16:00:56Z")

</div>

Sorry- I was wrong about not being able to test things on this Mac- I can. And dac\_cycle.mwel still doesn’t work.

Here’s the output of that command:

```auto
    Hardware Overview:

      Model Name: Mac mini
      Model Identifier: Macmini6,2
      Processor Name: Quad-Core Intel Core i7
      Processor Speed: 2.6 GHz
      Number of Processors: 1
      Total Number of Cores: 4
      L2 Cache (per Core): 256 KB
      L3 Cache: 6 MB
      Hyper-Threading Technology: Enabled
      Memory: 8 GB
      Boot ROM Version: 422.0.0.0.0
      SMC Version (system): 2.8f1

Graphics/Displays:

    Intel HD Graphics 4000:

      Chipset Model: Intel HD Graphics 4000
      Type: GPU
      Bus: Built-In
      VRAM (Dynamic, Max): 1536 MB
      Vendor: Intel
      Device ID: 0x0166
      Revision ID: 0x0009
      Metal: Supported, feature set macOS GPUFamily1 v4
      Displays:
        DELL D2015H:
          Resolution: 1920 x 1080 (1080p FHD - Full High Definition)
          UI Looks like: 1920 x 1080 @ 60 Hz
          Framebuffer Depth: 24-Bit Color (ARGB8888)
          Display Serial Number: FN8K9583A35I
          Main Display: Yes
          Mirror: Off
          Online: Yes
          Rotation: Supported
          Adapter Type: Apple Mini DisplayPort To VGA Adapter
          Automatically Adjust Brightness: No
          Adapter Firmware Version: 1.03
        DELL 2009W:
          Resolution: 1680 x 1050 (Widescreen Super eXtended Graphics Array Plus)
          UI Looks like: 1680 x 1050 @ 60 Hz
          Framebuffer Depth: 24-Bit Color (ARGB8888)
          Display Serial Number: G433H97GANKL
          Mirror: Off
          Online: Yes
          Rotation: Supported
          Automatically Adjust Brightness: No

2021-10-20 11:58:44.069 system_profiler[2534:38709] SPUSBDevice: IOCreatePlugInInterfaceForService failed 0xe00002be
2021-10-20 11:58:44.070 system_profiler[2534:38709] SPUSBDevice: IOCreatePlugInInterfaceForService failed 0xe00002be
USB:

    USB 3.0 Bus:

      Host Controller Driver: AppleUSBXHCIPPT
      PCI Device ID: 0x1e31 
      PCI Revision ID: 0x0004 
      PCI Vendor ID: 0x8086 

        USB Optical Mouse:

          Product ID: 0x4d81
          Vendor ID: 0x0461 (Primax Electronics)
          Version: 2.00
          Speed: Up to 1.5 Mb/s
          Location ID: 0x14300000 / 2
          Current Available (mA): 500
          Current Required (mA): 98
          Extra Operating Current (mA): 0

        Dell USB Keyboard:

          Product ID: 0x2105
          Vendor ID: 0x413c (Dell Inc.)
          Version: 3.52
          Speed: Up to 1.5 Mb/s
          Manufacturer: Dell
          Location ID: 0x14200000 / 3
          Current Available (mA): 500
          Current Required (mA): 70
          Extra Operating Current (mA): 0

        LabJack U6:

          Product ID: 0x0006
          Vendor ID: 0x0cd5
          Version: 0.00
          Speed: Up to 12 Mb/s
          Manufacturer: LabJack
          Location ID: 0x14100000 / 4
          Current Available (mA): 500
          Current Required (mA): 0
          Extra Operating Current (mA): 0

    USB 2.0 Bus:

      Host Controller Driver: AppleUSBEHCIPCI
      PCI Device ID: 0x1e2d 
      PCI Revision ID: 0x0004 
      PCI Vendor ID: 0x8086 

        Hub:

          Product ID: 0x0024
          Vendor ID: 0x8087 (Intel Corporation)
          Version: 0.00
          Speed: Up to 480 Mb/s
          Location ID: 0x1a100000 / 1
          Current Available (mA): 500
          Current Required (mA): 0
          Extra Operating Current (mA): 0
          Built-In: Yes

    USB 2.0 Bus:

      Host Controller Driver: AppleUSBEHCIPCI
      PCI Device ID: 0x1e26 
      PCI Revision ID: 0x0004 
      PCI Vendor ID: 0x8086 

        Hub:

          Product ID: 0x0024
          Vendor ID: 0x8087 (Intel Corporation)
          Version: 0.00
          Speed: Up to 480 Mb/s
          Location ID: 0x1d100000 / 1
          Current Available (mA): 500
          Current Required (mA): 0
          Extra Operating Current (mA): 0
          Built-In: Yes

            Hub:

              Product ID: 0x2512
              Vendor ID: 0x0424 (SMSC)
              Version: b.b3
              Speed: Up to 480 Mb/s
              Location ID: 0x1d180000 / 2
              Current Available (mA): 500
              Current Required (mA): 2
              Extra Operating Current (mA): 0
              Built-In: Yes

                IR Receiver:

                  Product ID: 0x8242
                  Vendor ID: 0x05ac (Apple Inc.)
                  Version: 1.00
                  Speed: Up to 1.5 Mb/s
                  Manufacturer: Apple, Inc.
                  Location ID: 0x1d182000 / 4
                  Current Available (mA): 500
                  Current Required (mA): 100
                  Extra Operating Current (mA): 0
                  Built-In: Yes

                BRCM20702 Hub:

                  Product ID: 0x4500
                  Vendor ID: 0x0a5c (Broadcom Corp.)
                  Version: 1.00
                  Manufacturer: Apple Inc.
                  Location ID: 0x1d181000

                    Bluetooth USB Host Controller:

                      Product ID: 0x828a
                      Vendor ID: 0x05ac (Apple Inc.)
                      Version: 1.50
                      Manufacturer: Apple Inc.
                      Location ID: 0x1d181300

```

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 20, 2021, 4:02pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/10 "2021-10-20T16:02:30Z")

</div>

Also- yes- this is a mac mini (late 2012) running 10.15.7.  
There is no external GPU.  
Lindsey.

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 26, 2021, 2:19pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/11 "2021-10-26T14:19:29Z")

</div>

Hi Lindsey,

Now I’m wondering if all this weirdness is due to a mismatch between the version of MWorks I built your plugin against and the version you’re running. It’s really never safe to use a compiled MWorks plugin with any version of MWorks other than the one you compiled it against, but usually the failure modes are obvious (e.g. MWServer crashes), so I hadn’t been thinking about it.

To test this theory, can you try installing the latest MWorks [nightly build](https://s3.amazonaws.com/mworks-downloads/nightly/MWorks-NIGHTLY.dmg) on this machine? Please _do not_ install any version of your U6 plugin (or any other non-standard plugins). Then, try loading and running the RSVP demo experiment, which is located at

```
/Library/Application Support/MWorks/Examples/RSVPDemo/RSVPDemo.mwel

```

If stimuli are still displayed on the main display, regardless of which display you select in MWServer’s preferences, then we can rule out this theory at least.

Thanks,  
Chris

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 27, 2021, 1:56pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/12 "2021-10-27T13:56:57Z")

</div>

Hi Chris,  
I installed the nightly and ran RSVPDemo, but the display is still on Display 1.  
But this wasn’t surprising since the display is fine on a bunch of other computers with the “unmatched” version of MWorks.  
Lindsey.

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [October 27, 2021, 2:13pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/13 "2021-10-27T14:13:58Z")

</div>

OK, thanks for checking. I’ll try to think of some other test to run next.

Chris

---

<div class="post-metadata">

**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\
**Post date:** [April 2, 2024, 1:19pm UTC](https://mworks.discourse.group/t/mworks-always-uses-main-display/97/15 "2024-04-02T13:19:23Z")

</div>