I just purchased an LG 34UM95. It's Rev02 November 2014. Given the conflicting experiences documented in this topic, I've tested it thoroughly in my usage scenario and am sharing my results.
I've tested the LG with the following equipment:
* 15" MacBook Pro with Retina Display (Mid 2012) running Yosemite
* 15" MacBook Pro with Retina Display (Late 2013) running Mavericks
FileVault is enabled on both MacBooks. A firmware password is set on the mid-2012 MacBook. Tthe following
System Preferences might also be important:
* Security & Privacy > General > Require password after sleep or screen saver begins is checked.
* Energy Saver > Power Adapter > Computer Sleep: Never. This might also be phrased as something like Don't sleep computer with display, depending on your Mac.
* Sound > Output: Select a device for sound output: 34UM95.
I connected the devices as follows:
* Mid-2012 MacBook to LG via ThunderBolt at 3440 x 1440 @ 60 Hz.
* Late-2013 MacBook to LG via both DisplayPort at 3440 x 1440 @ 60 Hz and USB uplink port.
* Keyboard connected to LG USB.
No volume control from OS X.
Confirmed. You can mute or unmute sound from OS X, but you cannot adjust the volume. Volume must be adjusted using the controls on the LG. As others have noted, this is probably because OS X thinks the LG is a television.
I don't think this is a huge problem. I'll either live with it or get a USB-based speaker system.
OS X thinks the LG is a television.
Confirmed. From
About this Mac, create a
System Report. Click
Graphics/Displays and then
NVIDIA GeForce GT. In the bottom pane, there will be a line that reads
Television: Yes.
It isn't clear to me that this means that color output is YCbCr instead of RGB. For example, if you check
System Preferences >
Displays >
Color, you'll find that OS X is using a display profile named
LG ULTRAWIDE. Click
Open Profile, and you'll see a line that reads
Space: RGB.
I don't see any image defects and the color looks fine to me. I did decrease brightness significantly to about 50 and contrast very slightly to 60.
Switching between inputs while MacBook is closed.
I typically keep my MacBook closed while using an external display. With the MacBook closed, I'm able to switch between the two Macs. The keyboard automatically follows the active display. All of this is flawless, except for the minor issues noted below, most of which are OS X
features, not incompatibilities.
When the Mac loses the connection to the monitor, it switches to the internal screen. This causes open windows to change size and location, so that they are still onscreen and visible. So, switching between inputs or turning the LG off will cause open windows to change size and location, as OS X ensures they are still located and visible on the only remaining screen.
Further, because I keep my MacBook closed, switching to the internal screen also causes OS X to sleep that display and lock itself. So, when I switch the input back to my Mac, I need to press a key, any key (e.g., the shift key), to get OS X to unsleep the display and send the LG a signal. At that point, I unlock the Mac and continue working.
Both of the above are OS X features, not problems with the LG display. The same thing would happen when using an Apple Thunderbolt display, if you unplugged the Thunderbolt cable. Effectively, when you switch inputs, you are unplugging the Thunderbolt or DisplayPort cable.
In my case, I can avoid almost all of the above issues by quitting apps, closing windows, or minimizing windows, before switching inputs. This works fine for me, because when I switch inputs, its because I'm making a major, medium-term task switch. Launching an app when I switch back to the Mac opens the original set of windows, at their original sizes, and in their original positions. If I only have the main window for an app open (e.g., Mail), closing the window before I switch inputs and clicking the app in the dock after switching back to the Mac does the same. Minimized windows generally survive switching inputs, and restore to their original locations and in their original sizes.
One last item: if the device connected to the current input of the LG is disconnected or sleeps the display, I need to wait until the light below the LG logo goes off before I can bring up the LG menu and change inputs. I'm guessing that the LG is still trying to re-establish the connection on the currently selected input and can't bring up the menu until it times out.
Docking and undocking the Mac
This works flawlessly. Starting with either MacBook closed and displaying on the LG, you can do the following:
* Sleep or shutdown.
* Disconnect power and either Thunderbolt or DisplayPort and USB.
* Use the MacBook as a notebook computer.
* Sleep the MacBook by closing the lid.
* Connect power and wait for the status light on the MagSafe connector to turn on. Give it a brief extra moment to figure out if the MacBook needs to be charged.
* Connect either the Thunderbolt or the DisplayPort and USB.
* Wake the Mac using the keyboard attached to the LG.
Restarting the Mac
Here's the only place where I found behavior differed between the mid-2012 MacBook over Thunderbolt and the late 2013 MacBook over DisplayPort with USB.
Over Thunderbolt, the LG worked perfectly during the restart. However, none of the USB devices connected to the LG were recognized until after I had logged in at the FileVault login screen. As a result, you'll need one of the following workarounds: (i) a USB keyboard, either directly connected to the Mac or connected to a USB hub that is directly connected to the Mac; or (ii) an Apple Wireless Keyboard. I haven't tested the latter, but since my Magic TrackPad works fine at the FileVault login screen, I'm assuming the Apple Wireless Keyboard will too.
Over DisplayPort, nothing was visible on the LG during restart. In fact, at least once, even opening the MacBook didn't result in displaying the FileVault login on the internal screen, and I needed to hold the power button for five or more seconds to force a shutdown. However, with the MacBook open, restarting was 100% reliable, including the USB connection to the keyboard through the LG. The FileVault login was displayed on the internal screen, and the LG became active after login. In this case, the workaround is to only restart when the Mac is open.
An alternative workaround to both of the above is to simply never restart the Mac while connected to the LG. Undock it. Restart it. Log in. Dock it.
Personally, I'm going to use Thunderbolt and a directly connected USB hub. There are certain USB peripherals that I don't want to share between the two connected computers anyway.
