Controlling brightness on two 24" LED Cinema Displays

I have an 8-core Mac Pro from this summer with two NVIDIA GeForce GT 120 cards and two 24" LED Cinema Displays. I'm running Snow Leopard 10.6.1, and when I try to adjust the brightness, the slider on both panels controls only one monitor. I therefore can't adjust the brightness of one of my displays. Has anyone found this?

I filed a bug report at bugreporter.apple.com, and received a pretty quick reply:
This is a follow up to Bug ID# 7222745. After further investigation it has been determined that this is a known issue, which is currently being investigated by engineering. This issue has been filed in our bug database under the original Bug ID# 6828443. The original bug number being used to track this duplicate issue can be found in the State column, in this format: Duplicate/OrigBug#.
Looks like I'm S.O.L. until they fix this!

Similar Messages

Adjusting brightness with two 24" LED Cinema Displays

I'm wondering if there are any other Mac Pro users out there with two 24" LED Cinema Displays? If so, are you able to adjust the brightness of both displays? For me, no matter which brightness slider I adjust in System Preferences, only the brightness of one of the displays is adjusted.
I originally created a thread last September:
http://discussions.apple.com/thread.jspa?threadID=2160532
If you have this problem too, please report it to <http://bugreporter.apple.com/>. My original Radar bug was #7222745, and it was found to be a duplicate of #6828443. Based on the IDs, I'd say this has been a known issue for at least a year.
Thanks,
Patrick

I filed a bug report at bugreporter.apple.com, and received a pretty quick reply:
This is a follow up to Bug ID# 7222745. After further investigation it has been determined that this is a known issue, which is currently being investigated by engineering. This issue has been filed in our bug database under the original Bug ID# 6828443. The original bug number being used to track this duplicate issue can be found in the State column, in this format: Duplicate/OrigBug#.
Looks like I'm S.O.L. until they fix this!

Does anyone have two 24" LED Cinema Displays on their Mac Pro?

I'm wondering if there are any other Mac Pro users out there with two 24" LED Cinema Displays? If so, are you able to adjust the brightness of both displays? For me, no matter which brightness slider I adjust in System Preferences, only the brightness of one of the displays is adjusted.
I originally created a thread last September:
http://discussions.apple.com/thread.jspa?threadID=2160532
If you have this problem too, please report it to <http://bugreporter.apple.com/>. My original Radar bug was #7222745, and it was found to be a duplicate of #6828443. Based on the IDs, I'd say this has been a known issue for at least a year.
Thanks,
Patrick

I am using logitech G19 mouse and Naga Razer Epic, my current suspect that is their official driver which make my OS X 64bit kernl go nut. Does Logitech Control Center work for later version of their products such as G19?
If I plggued in the G19 without installing their official gamepanel software, The heyboard still work, volume control slider works like a charm. I just get no advantages from the LCD screen (kind of pointless).
If I install the razer mac driver, I keep seeing error log in console for the kzcorengineand razercorenginer process.
Idid clean install of Mac OS X and have not experienced freeze except once when I was plugging in my 500gb transcend external drive. This Ext. Drive require two usb slot for power and transfer data.
I am not sure if the freeze was coincidental or related to the transcend external drive I used. I did a directory permission repair and a repair to the mac drive, how things seems to stabilised.
However I want to take my test further to install office 2011 to see if it cause those random unpredictable freeze again.
Sigh, I paid $200 for such a good keyboard, but they have bad apple support. I dont like the apply ketyboard and magic mouse. It's immpossible to touch type on and even harder to play any game at all.
Wayne, when you use your logitech product, do you install the product specific driver for each product plus LCC? or you just install LCC.
Thank you

Two 24" LED Cinema display and getting audio from both

I have two 24" LED Cinema displays connected to a MP. Is there a way to get the audio to play through the speakers on both displays at the same time? I can easily switch the USB audio to either display, but I cannot figure out how to play audio through both at the same time. Thank you for the help,

You can hijack the audio from any application, or the system audio, with Audio Hijack Pro
<http://www.rogueamoeba.com/audiohijackpro/>
You can then use its Auxiliary Device Output effect to send the audio to multiple devices.

Brightness Control and 2 x 24" LED Cinema Display

I think I've discovered a bug with the Display System Preferences panel.
I have a new 2009 Mac Pro with one ATI 4870 and one Nvidia GT120, each having a 24" LED Cinema Display attached. When I keyboard brightness buttons (F1,F2), only the one display changes brightness. When I use the sliders on the Display System Preferences panel, both sliders control the one display. So I can change the brightness of one display 3 different ways, but no way to control the other (or both at the same time, which is most desirable).
What is even more interesting, is that the controllable panel changes depending on which monitor's USB connector is connected into which USB port and in what order they are connected. After trying different USB combinations, I once got the slider on the left screen to control the brightness of the right screen, and vice versa, but the controls are seemingly randomly reassigned on system sleep, and I havent been able to duplicate that behavior since.
What is the best way to report this? It appears to be a bug in the USB code associated with the brightness sliders and the Display Preferences panel. My desired behavior would to have the keyboard buttons control the brightness of both displays at the same time.
Thank You

No problem with my 24" and a 2008 Mac Pro with an nVidia GE120. I'm betting that the problem isn't with the monitor but with the video card. I also have a unibody Mac Book Pro and discovered the color shifting problem without any monitor attached. It started occurring when I used my Huey Pro Pantone monitor calibrator on the LED display of the MBP. Recalibrating the display exposes the color shift. Putting the monitor back to the shipping calibration makes the display problem go away completely.
At the same time, I never noticed any problem on the 24" cinema display before calibrating it, and exposing it to the hardware monitor calibrator exposed a way out of gamma color. After recalibrating the monitor in hardware, the picture is utterly flawless - best I've ever seen on a display of this size. I think the Apple software calibrator is a piece of junk and I suspect that it messes with the monitor in unhelpful ways. I'd suggest having the monitor professionally calibrated and see if that cures the problem.
Also, it will be interesting to see whether anything in the 10.5.7 update fixes any display issues being reported prior to the release yesterday.

Problem w/ two 27" LED Cinema Displays on ATI 5770 MacPro

Attempting to connect a second display to a mid 2010 Mac Pro. There are two mini-ports + a DVI on the 5770 card. Currently I have a single 27" LED connected using one of the mini ports. The computer isn't recognizing the second monitor in the other mini port. I used to have an older 24" LCD Cinema display running successfully, using the DVI port on card with a powered adapter. That configuration isn't doable with a newer 27" given the output from it (not the older style video cabling, but rather the mini display port. Would appreciate any suggestions on how to get the two 27" monitors running together.

Hey turbostar, finally a chance to get back to you, sorry about the delay.
I had already tried both ports with no success on the second monitor, but when I moved the primary monitor to the second port and it worked... it it got me to thinking maybe the power outlet was bad if not the monitor itself. Indeed that was the issue. The second monitor was plugged into a power strip in which one of the six outlets on it was not working. Replaced the surge power strip with a new one and all is good.
Thank you for your time and help.

Two 24" LED Cinema Displays from 2009 Mac Mini?

I have been using two 24 inch Samsung's with a Mac mini for about 6 months and it's been great until one of the monitors failed me last week. After some research I purchased a new 24" LED ACD and it's a beautiful monitor that blows away my other 24" Samsung. I'm thinking about getting another 24" LED ACD and my question is: Has anyone connected 2 24" LED ACD's to a Mac mini using: http://www.atlona.com/Atlona-DVI-to-Mini-DisplayPort-Converter-p-17859.html
My plan is to use the mini display port to connect one ACD and use the Atlona Converter to connect the other ACD through the mini DVI port on the Mac Mini. I have the Atlona converter ordered and it will be here early next week and I'll report back on the results unless someone else has already done this and knows it works.

Jim Stewart1 wrote:
Just one further question, though - doesn't that mean I lose out on other uses for the Mini's only Thunderbolt port?
No, because Thunderbolt can be daisy chained. Just make sure that whatever Thunderbold Drive Enclosure you get, has dual Thunderbolt ports so that you can chain your second monitor to it.
see > Displays: Mini DisplayPort display must be last in a Thunderbolt chain
Also, can I ask why you suggest putting the 20" on HDMI? If it came to running a single monitor + Thunderbolt RAID setup, I'd like to have the 23" on the HDMI.
Mostly because the Thunderbolt/Mini DisplayPort supports higher resolutions than the HDMI port.
HDMI to DVI only supports 1920x1200
Thunderbolt port supports 2560x1600
Would that be problematic?
Not as long as the 23" monitors native resolution is 1920x1200 or less.

How do you connect two 27" LED Cinema Displays together?

I currently have one screen connected to my MacBook Pro 2010. How do I connect the second screen if I only have one Thunderbolt port?

I Think they can be daisy chained.check your manual for more info to see if your Mac supports this
John b

Select Default iSight Cam with Dual LED Cinema Displays

Hello
I have two 27in LED Cinema Displays, both of which have iSight Cameras. When I try to facetime, by default, the right monitor camera turns on, but I want to use the left camera.
How do I select which camera on which monitor I want to use? Both monitors are connected via thunderbolt. I'm using OS X Mavericks.
Thanks!

You can try the old trick of first launching a camera app that you do NOT want to use - QuickTimeX > New Movie Recording perhaps - to have it engage the ONE display iSight camera. After you can see that your camera is engaged with the unwanted app, you can hide that app if desired. Then launch FaceTime and see if the other connected camera is accessible to FaceTime.
If FaceTime cannot then recognize the second Display iSight, check your System Information utility to see if your Hardware > USB > USB Device Tree recognizes both Display iSights. If the device tree recognizes only one Display iSight, your lowest cost workaround may be to connect a Mac-compatible webcam to one of your available USB ports so it is recognizable . The external camera may then be selectable in your FaceTime menu without the two-application trick.
Message was edited by: EZ Jim
Mac OSX 10.10.2

Controlling Brightness on Dual LED Cinema Displays

I got my mac pro and 2 x LED cinema display yesterday, very pleased with the whole setup (ordered a couple of extensions for the displayport cable after looking around in threads on here too). Something that bugs me a little though is that it seems only possible to control the brightness of the display connected to the graphics card in slot 1. using f1 and f2 adjusts this display's brightness but not the secondary monitor, likewise the system preferences display panel shows a brightness slider for each display, yet both sliders adjust the brightness of the same display.
I assume this is a software issue and will be fixed either in the next build of leopard or in snow leopard, but am just wondering if anyone has found a workaround / some kind of keyboard shortcut I'm missing or anything?

You are not alone:
<http://discussions.apple.com/thread.jspa?threadID=1988252&start=0&tstart=0>
There is one report (Filchescat) of it working correctly (apart from the Windows 7 user, whose brightness keys control three 24" displays).
I don't see how Apple can make independent brightness control of external displays work from the computer. The brightness is controlled via the USB cable. Unless each display sends a serial number through both its USB and display ports, how is the computer going to know which USB port corresponds with which display. System profiler doesn't seem to show serial numbers for displays or USB devices.

27" LED Cinema Display, no brightness control

I have a 27" LED Cinema Display that has the Mini DisplayPort cable and I am plugging into a MacbookPro 15" with a thunderbolt port. When I go into System Preferences there is no brightness control or ability to turn off automatic adjustment for the LED display, just the computer. I have the usb port plugged in as well. I have seen previous updates to fix this for earlier versions (10.6) but that didn't work on my OS X 10.8.2. Is there anything to remedy this? The automatic adjustment of brightness is very distracting and I would like to have control of the brightness of my monitor.

FINAL NOTES
It’s possible that the issue might simply be resolved when applying both a Software and a Firmware update for the LED Cinema Display. If you haven’t already, please download and install the following to see if these updates resolve the issue:
http://support.apple.com/kb/DL1338
http://support.apple.com/kb/DL1107
Secondly, if you are using Mac OS X 10.8 (Mountain Lion) or Mac OS X 10.9 (Mavericks), please try this additional Software Update for the LED Cinema Display if you haven’t already installed it:
http://support.apple.com/kb/DL1613
Additionally, my research into other customers’ cases with these issues (brightness controls and USB functions not behaving correctly) regarding the LED Cinema Display shows that the following method might fix your issue: When connecting the affected LED Cinema Display into your Mac Pro, first plug the USB connector into the Mac, then plug the Mini-Display connector into the Mac, and finally re-open System Preferences to see if the brightness controls have returned.
That mentioned just previously is worthless for those with an updated operating system but is mentioned regardless.
As it works out those installers will not allow installation and merely state that you don't need this software in updated systems.
They require that you make a brand new OS installation to be of any effect and are included in Software Updates.
They are worth a try if all else fails.
You should also try Disabling your Bluetooth "Discoverable" setting.
The Discoverable Bluetooth setting seeks to establish a wireless USB connection and depending on your RF environment, can become very busy if not conflicted. (can override a wired USB connection)
Last but certainly not least.
Do NOT connect your monitor USB through a USB hub.
Internally your monitor has a USB hub.
Connecting a USB hub TO a USB hub is just asking, (if not blatantly begging), for problems.

I have a macbook connected to LED cinema display. The display started to flicker. The display turns black for a second or two. Sometimes I restart macbook and display. Sometimes it helps.

I have a macbook connected to LED cinema display. The display started to flicker. The display turns black for a second or two. Sometimes I restart macbook and display. Sometimes it helps.

same issue, either your wiring or display itself is going bad. for me, it was the display but luckily still under warranty

Can't control volume on LED Cinema Display from keyboard

I have a LED Cinema Display attached to my Mac Mini. The volume control buttons on the keyboard don't work anymore. The only way I can change the volume is to use the volume control on the video I am watching. I tried the headset trick on the output port on the Mini, and now that works with the volume keys. But, the display volume is still not working. Any hints?

The reason why that has happened in the first place is because MAC OS, is programed to not adjust the volume through an HDMI interface. If you have the volume control shown on the upper bar like i do, it appears light grey.When you click on it you cannot move it up or down. This is of course what the keyboard controles for volume. It does not control the program.

27 LED Cinema Display Audio and Brightness when powering MacBook Pro

When my 27 LED Cinema Display is powering my (or another) 2009 13" MacBook Pro, I have experienced three issues:
1. The dropped audio problem other users have mentioned. Shutdown, then disconnect power/usb/displayport, then wait ~15s, then reconnect and reboot temporarily fixes the problem.
2. I also have the sluggish keyboard behavior when adjusting the volume that others have mentioned.
3. I have experienced shifts in display brightness which are obvious when the display is dimmed. I have disabled the ambient light sensor as well as any interfering power management or energy saver settings. Opening apps, scrolling and other normal activities seem to aggravate this behavior.
This last strange behavior inspired me to try using a power adapter for the MacBook Pro instead of display's laptop power connector. *Doing so seems to have resolved all three issues.*
It seems that this may indicate an underlying problem with the display's power supply. Can anyone confirm?

mmayo wrote:
I am having the same issues & with a 1 day old display. I am using a 15" MBP. The screen is killing me when it dims down when no lights are on. I didn't notice the issue when the screen is brighter with the lights on. Anyone know if this is a hardware or software issue? I'd like to utilize the ambient light sensor but not if its going to make my screen flicker when it is dim....
(1) I have never had any deaths associated with my screen, but on rare occasions my display's brightness will flicker when I manually adjust the brightness. The fix I have found for this is to increase the brightness one more setting or decrease it one more setting. Changing the screen from full dim to full bright and then setting the brightness I want sometimes helps, too.
(2) You can check whether this software update has been applied to your 27-inch:
http://support.apple.com/kb/HT4293
(3) Your Apple Service Provider could tell you whether your problem is related to hardware or software.
Mac Pro Quad Core (Early 2009) 2.93Ghz Mac OS X (10.6.4); MacBook Pro (13 inch, Mid 2009) 2.26GHz (10.6.4)
LED Cinema Display; G4 PowerBook 1.67GHz (10.4.11); iBookSE 366MHz (10.3.9); External iSight; iPod touch 4.1

New MacBook Pro & 27" Apple LED Cinema Display Don't Go to Sleep

I recently purchased a new 13" MacBook Pro (MacBookPro8,1) and a 27" Apple LED Cinema Display. When they are connected the computer occasionally has a problem being put to sleep. When clicking sleep, the monitor will take a little while to shut off, but in about 10 seconds, it will turn back on. Immediately when turning on, the image on the screen is quite scrambled (it does correct itself). Usually, if I attempt to put it to sleep multiple times, it will end up working. When it does go to sleep (correctly), the screen will turn off much faster than the times where it doesn't sleep.
Anyone else have a similar issue they found a fix to? When speaking to Apple support, they thought it was part of an issue with 10.6.6, however, the update to 10.6.7 did not solve the issue.
PS - I keep my MacBook Pro lid closed when using the display.

Is your 2.6 the CTO upgrade from the high end 2.3 15"?
Yes, both will work under OSX and Windows. One note, when you boot Windows, you need to unplug the USB from the LED Cinema display or Windows will not boot. Once booted, then plug the USB back in to regain brightness, etc controls.

Controlling brightness on two 24" LED Cinema Displays

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