Multiple Monitor Issues with OS X 10.9 (Mavericks) and 10.10 (Yosemite)

Update 10/22/14: With the release of 10.10 (Yosemite), unfortunately there’s not much improved USB graphics behavior to report, as the key issues outlined in this post still exist.

We’ve posted an update regarding USB graphics and other USB device behavior with Yosemite that can be found here.

DisplayLink has recently released an updated beta driver that contains some fixes, though the larger issues outlined in this post and elsewhere are still present. Beta driver v2.3 is compatible with OS X 10.8.5, 10.9.x, and 10.10.

Original Post 10/22/13: OS X 10.9 (“Mavericks”) has been released today and is a free update.

But multiple monitor users should hold off – OS X 10.9 appears to break many multiple monitor setups.

At least 4 distinct issues with external displays have been duplicated on the “Golden Master” developer seed OS X 10.9. There are no known workarounds or resolutions available at this time:

  1. HDMI displays cause unexpected mirroring
  2. Display Preferences lost on reboot or hot plug
  3. A significant performance drop from 10.8.5 on USB attached displays
  4. Window server crashes

We have already created a bug report with Apple on the first issue, HDMI displays causing unexpected mirroring. However, Apple has not yet responded to it. In an effort to get more traction on this bug, we’ve created an OpenRadar bug report. We need your help to gather more information. Please leave a comment on the OpenRadar bug report with your system information and any relevant setup details.

HDMI displays cause unexpected mirroring
Apple does not make bug reports submitted to them visible to others, so we are showing that report here. Apple has not yet responded to it. This bug affects DisplayLink-based hardware (like ours), along with other HDMI setups using non-DisplayLink hardware. Because this bug report was based on testing with 10.9 preview releases, the behavior might be better or different in the final OS X 10.8 final release version.

Submitted Apple Bug Report: HDMI displays create mirror issues under 10.9 GM seed

When attaching additional displays beyond a single primary display, HDMI attached displays will override a user’s display preferences (resolution and arrangement of additional displays).

This has been tested and reproduced using both USB to HDMI adapters, Thunderbolt to HDMI adapters, and the HDMI output built-in to a current gen USB 3.0 Mini.

When using a HDMI to DVI adapter (Apple branded or 3rd party), the issue is not reproduced: the error seems to be triggered specifically by HDMI (regardless of whether the HDMI is a built-in port, a Thunderbolt to HDMI adapter or cable, or a USB to HDMI adapter.

To be clear, I AM able to use a mix of DVI or VGA attached displays without hitting this issue: the issue only occurs when attempting to add an HDMI display.

After manually disabling mirroring and arranging the displays, they will work normally- however the issue will recur on reboot and typically whenever the HDMI display is re-attached. In the case of the Thunderbolt to HDMI cable or adapter or a USB to HDMI adapter (DisplayLink 2.0 and 3.0 based), a reboot or hotplug event will “break” the non-mirrored display arrangement—although anything other than “deep” sleep does NOT. That is to say display arrangement is retained until the system reboots or enters deep sleep, or on hot-plug events.

Please note that similar issues were seen on earlier 10.9 builds, however these actually got worse on the GM seed pushed 10/7/13.

Steps to Reproduce:
1. Use a normally working 10.9 Mavericks system with built-in Thunderbolt and HDMI display outputs.
2. Attach any HDMI display via built-in HDMI port, USB to HDMI display adapter, or Thunderbolt to HDMI adapter/cable.
3. Observe that HDMI display comes up in mirror mode rather than as an extended display.
4. Disable display mirroring, arrange displays to match physical locations.
5. Reboot system: observe that display preferences are lost.

6. Repeat, substituting a DVI or VGA connection to the same HDMI display. Observe that mirror mode issue is not encountered, and that display preferences are retained up on reboot.

Expected Results:
Displays should come up in “extended” mode, regardless of how they are attached.

Actual Results:
In my testing on 3 Mavericks systems, any HDMI display comes up in mirror mode, and causes display preferences to be lost on reboot (and various other conditions previously mentioned).

Version:
OS X 10.9 (13A598)

Submitter:
Jeff Everett (support@plugable.com)

Display Preferences Lost on Reboot or Hotplug
Distinct from the issue where HDMI displays cause unexpected mirror mode configurations, display preferences like monitor arrangement, resolution, and background are almost always lost on reboot and “hotplug” events when USB display adapters are unplugged and then reconnected. This means users may have to re-configure the OS X settings relating to physical arrangement of their multi-display systems on every reboot or every time they have to disconnect/reconnect from their USB display devices.

No or Slow Rendering on USB Attached Displays
An occasional problem when running 2 or more USB attached displays is that the displays won’t update most pixels. Mouse cursor movement is visible, however any updates made by applications onscreen are not visible, leaving the external display unusable.

Window Server Crashes
Although infrequent, the window server can crash. This renders a system unusable as all displays repeatedly go black/blank while the window server restarts.

Investigation is ongoing as to whether these issues are “core” OS issues with 10.9 Mavericks or may be resolved by further updates to DisplayLink’s 2.1 beta driver. At least one issue (with HDMI displays creating unexpected mirroring) appears to be a fundamental OS X issue, as this has been reproduced on a system with no DisplayLink driver installed, using only the HDMI and Thunderbolt ports built into a late 2012 Mac Mini 6,1.

Additional details are available on DisplayLink’s “Known issues with DisplayLink on OS X 10.9 Mavericks” page, as well as in their OS X 2.1 beta driver forum.

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