Q: Mac Pro Late 2013 and Samsung 4k monitor problem

I'm not 100% positive of the settings, since I don't have the AMD card anymore.  But I'm pretty sure all I did was create a custom resolution  CVT-RB simplified settings w/ a 50Hz refresh rate, leaving the default settings for horizontal sync (pos) and vertical sync (neg).  Then save, reboot, and use SwitchResX to select the new 50Hz mode.

You might need to create the scaled resolutions if you want 50Hz versions of the lower resolutions (hidpi) - I just run mine at native, so I can't remember the steps involved, though I remember something about having to create 2x resolutions of each resolution you want.  There might be more info at the switchresx website or forums....

BTW:  Does the nMP give a boot image on a 4k single-stream monitor?

I can confirm that setting the screen to 50Hz with SwitchResX does in fact get rid of the distortion issue.  This is much better than default with distortion.

This is the settings the app created when I set the Hz on Vertical to 50Hz

Excellent! The above information from Rave-TZ and DanielHartman1 allows me to run my U28D590D using 3840x2160 @ 50Hz via DisplayPort. Thanks! There is no tearing of the right side of the screen, and it is much more responsive than the 30Hz I was getting with HDMI.

However, I have been trying to enable a scaled resolution of 2560x1440 HiDPI @ 50Hz, but haven't had any success. I can only do it at 60Hz (with tearing) or 50Hz (low resolution, not a nice scaled HiDPI). Any further advice would be greatly appreciated! I've been trying/searching for half the day!

Kind regards,

Poyda

This thread might help.  Looks like you need to create a custom, "scale resolution" of 5120x2880.  Haven't tested yet, but this sounds like what I remember - you should end up with a 5120x2880 mode, and a 2560x1440 hidpi mode.

http://forums.macrumors.com/showthread.php?t=1568657

You might also want to disable all the 60hz resolutions in the "current resolutions" tab - if you use the switchresx menu to swap resolutions, it'll cut down on the number of options to sort through.

Unfortunately all of the scaled resolutions I make are at 60Hz. There is no way to specify the refresh rate when making a scaled resolution, only when I make a "custom" resolution.

Additionally, I can't create a custom (non-scaled) resolution above 4096 pixels horizontal, but I think that shouldn't matter, because the one I want to make is a scaled resolution... Any more ideas?

Thanks again!

I sent the developer of SwitchResX an email asking if it was possible, here is the reply:

You cannot define which resolution is used as a basis for the scaled resolutions. Scaled resolutions are all "children" of a master resolution, which is always the same, and which is chosen by MacOS X - this is not a choice that can be influenced by SRX

Moreover, as far as I know, Apple has decided that AMD display drivers cannot use scaled resolutions apart those that are stored in a hardcoded list in their display driver. I may be wrong, but this simply means that you cannot get any HiDPI resolution that is not "apple-approved" on a MacPro.

 

regards

Stephane

That's very unfortunate news for me, because I find the interface to be way too small to use at the native resolution of 3840x2160. At least we have made some progress. Let's hope Apple and AMD hurry up and fix this problem soon.

Thanks,

Poyda

Poyda wrote:

 

I sent the developer of SwitchResX an email asking if it was possible, here is the reply:

You cannot define which resolution is used as a basis for the scaled resolutions. Scaled resolutions are all "children" of a master resolution, which is always the same, and which is chosen by MacOS X - this is not a choice that can be influenced by SRX

Moreover, as far as I know, Apple has decided that AMD display drivers cannot use scaled resolutions apart those that are stored in a hardcoded list in their display driver. I may be wrong, but this simply means that you cannot get any HiDPI resolution that is not "apple-approved" on a MacPro.

 

regards

Stephane

 

I know that Mountain Lion was the last version I was able to create scaled resolutions that are greater in size than the native display size for the Radeon HD 5870 (for HiDPI testing). Apple removed the feature for no good reason. I don't know if Apple has changed that since then because I use an NVIDIA GTX 680 now. It seems that OS X drivers for NVIDIA and AMD are developed separately and don't maintain feature parity.

But Poyda said he was able to create the scaled resolutions that he wanted - they were just using the native timing of the display instead of the new 50 Hz timing. So to solve this, you have to figure out how to make the driver think that 50 Hz is the native timing of the display. The only way I can think to do that is to override the EDID of the display. It may or may not work though.

To override the EDID for the U28D590D you need to create an override file at /System/Library/Displays/Overrides/DisplayVendorID-4c2d/DisplayProductID-b80

Here's a version of an override file for the U28D590D with the preferred timing set to 50 Hz:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>DisplayProductID</key>
  <integer>2944</integer>
  <key>DisplayVendorID</key>
  <integer>19501</integer>
  <key>IODisplayEDID</key>
  <data>AP///////wBMLYALAAAAADQXAQS1PSN4Ol+xoldPoigPUFS/74BxT4EAgcCBgKnAswCVANEAqKwAoPBwPoAwIDUAX1khAAAaVl4AoKCgKVAwIDUAX1khAAAaAAAA/QAySx6GNgAKICAgICAgAAAA/ABVMjhENTkwCiAgICAgAW4CAwzwIwkHB4MBAAACOoAYcTgtQFgsRQBfWSEAAB4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlw==</data>
</dict>
</plist>

Have you tried refresh rates higher than 50 Hz? 56 Hz is the highest before the pixel clock exceeds 500 MHz which might be a possible limit of the driver. Here's the same override with the preferred timing set to 56 Hz.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>DisplayProductID</key>
  <integer>2944</integer>
  <key>DisplayVendorID</key>
  <integer>19501</integer>
  <key>IODisplayEDID</key>
  <data>AP///////wBMLYALAAAAADQXAQS1PSN4Ol+xoldPoigPUFS/74BxT4EAgcCBgKnAswCVANEAC8IAoPBwPoAwIDUAX1khAAAaVl4AoKCgKVAwIDUAX1khAAAaAAAA/QAySx6GNgAKICAgICAgAAAA/ABVMjhENTkwCiAgICAgAfUCAwzwIwkHB4MBAAACOoAYcTgtQFgsRQBfWSEAAB4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlw==</data>
</dict>
</plist>

The EDID of the U28D590D says the minimum vertical refresh is 56 Hz so I am not sure why the driver would ignore that and allow your custom 50 Hz timing but since you got it to work, I've updated the EDID to show 50 Hz as the minimum refresh.

If you used SwitchResX to create an override then there might be a file named DisplayYearManufacture-2013-DisplayWeekManufacture-52. Just check the DisplayProductID and DisplayVendorID inside the file to be sure or you could use the "Restore factory settings" option in SwitchResX first before creating the DisplayProductID-b80 file. I'm guessing the Year/Week file created by SwitchResX takes precedence over the ProductID file or SwitchResX removes the ProductID file.

Oh wow! It works!!! Thanks so much joevt! (and everyone else that has helped!)

Before trying the custom EDID that you created, I tried using SwitchResX to create custom native resolutions (3840x2160) at refresh rates above 50 Hz. The highest I could get without causing the tearing on the right side of the screen was 54 Hz. Here is the screenshot of the settings at 54 Hz:

Because I couldn't reach 56 Hz at the native resolution, I did not try to apply your custom override file with the preferred timing set to 56 Hz. However, I did try the 50 Hz version, and it works magnificently

Firstly, I reset to factory default settings in SwitchResX, then restarted the computer.

/System/Library/Displays/Overrides/DisplayVendorID-4c2d/     was empty after I restarted, so I created a file called "DisplayProductID-b80" and pasted in the 50 Hz version of your override code. After a quick reboot, all of the resolutions were available at 50 Hz, including the scaled HiDPI ones!

You're an absolute champion, joevt. If it's not too much trouble, do you think you could create an override file with a preferred timing of 54 Hz? I don't really know if I'd notice the difference between 50 and 54 Hz, but I assume that faster is better (all good if you can't be bothered, I'm very happy already!)

Thanks again, I hope everyone else can recreate the same success with their shiny new 4K monitors!

Poyda

I noticed your screen shot isn't using the CVT-RB calculation. It's using the vertical blanking values of the 60 Hz timing. That made me realize that I forgot to update the Blanking value in the overrides that I gave. Here's some updated EDIDs with the correct blanking values to conform to SwitchResX's CVT-RB calculation:

50 Hz (442.00 MHz):

<data>AP///////wBMLYALAAAAADQXAQS1PSN4Ol+xoldPoigPUFS/74BxT4EAgcCBgKnAswCVANEAqKwAoPBwM4AwIDUAX1khAAAaVl4AoKCgKVAwIDUAX1khAAAaAAAA/QAySx6GNgAKICAgICAgAAAA/ABVMjhENTkwCiAgICAgAXkCAwzwIwkHB4MBAAACOoAYcTgtQFgsRQBfWSEAAB4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlw==</data>

54 Hz (478.50 MHz):

<data>AP///////wBMLYALAAAAADQXAQS1PSN4Ol+xoldPoigPUFS/74BxT4EAgcCBgKnAswCVANEA6roAoPBwOIAwIDUAX1khAAAaVl4AoKCgKVAwIDUAX1khAAAaAAAA/QAySx6GNgAKICAgICAgAAAA/ABVMjhENTkwCiAgICAgASQCAwzwIwkHB4MBAAACOoAYcTgtQFgsRQBfWSEAAB4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlw==</data>

55 Hz (487.50 MHz):

<data>AP///////wBMLYALAAAAADQXAQS1PSN4Ol+xoldPoigPUFS/74BxT4EAgcCBgKnAswCVANEAbr4AoPBwOYAwIDUAX1khAAAaVl4AoKCgKVAwIDUAX1khAAAaAAAA/QAySx6GNgAKICAgICAgAAAA/ABVMjhENTkwCiAgICAgAZsCAwzwIwkHB4MBAAACOoAYcTgtQFgsRQBfWSEAAB4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlw==</data>

56 Hz (496.75 MHz):

<data>AP///////wBMLYALAAAAADQXAQS1PSN4Ol+xoldPoigPUFS/74BxT4EAgcCBgKnAswCVANEAC8IAoPBwOoAwIDUAX1khAAAaVl4AoKCgKVAwIDUAX1khAAAaAAAA/QAySx6GNgAKICAgICAgAAAA/ABVMjhENTkwCiAgICAgAfkCAwzwIwkHB4MBAAACOoAYcTgtQFgsRQBfWSEAAB4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlw==</data>

57 Hz (505.75 MHz):

<data>AP///////wBMLYALAAAAADQXAQS1PSN4Ol+xoldPoigPUFS/74BxT4EAgcCBgKnAswCVANEAj8UAoPBwO4AwIDUAX1khAAAaVl4AoKCgKVAwIDUAX1khAAAaAAAA/QAySx6GNgAKICAgICAgAAAA/ABVMjhENTkwCiAgICAgAXECAwzwIwkHB4MBAAACOoAYcTgtQFgsRQBfWSEAAB4AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAlw==</data>

Just got back to follow the progress of this thread.

Good news people! Will try this out this evening if I can get my head round it myself.

from what I gather from poydas success, the process is to

1. restore switch res to factory settings

2. Create an override using the code that joevt has written above for one of the timings in

/System/Library/Displays/Overrides/DisplayVendorID-4c2d/DisplayProductID-b80

(what should the file extension be?)

3. switchres should then allow selectable resolutions at the timings which work for our display ports and we can finally use them with a respectable result.

Please correct me if I'm wrong or if there are any pitfalls you can foresee for me or others, be good to get it working tonight

L

Laseyman, that's pretty much it! The filename for the override must be "DisplayProductID-b80" (no quotes, no extension). I haven't tried joevt's updated codes yet (with the corrected blanking value), but I've been using his earlier 50 Hz one for many hours without any problem. I will try the newer ones later and see how high I can get the refresh rate.

EDIT: I'm not even using SwitchResX now. Just using the Displays preference pane in system preferences. It does work in SwitchResX though.

Excellent Poyda,

I was going to ask if the overrides work for the system prefs too as it's not just switch res that would look to that folder I assumed?!

Let us know if you get any problems, I've had a couple of screen power downs that lasted 2-3seconds that I'm hoping was just due to the hdmi connection. Will be keeping my eye out for any problems in the future too. I'll sort it out tonight and post either way.

Laseyman wrote:

 

I was going to ask if the overrides work for the system prefs too as it's not just switch res that would look to that folder I assumed?!

The overrides folder is created by Apple to be used by Apple's graphics drivers. System Preferences uses the graphics drivers.

The files in the overrides folder contain information about displays that are not included in their EDID and/or to override their EDID.

SwitchResX works by modifying or creating a folder/file for your display in the overrides folder.

I've tried to get this going for an hour and a half now to no avail. I'm trying it with the 50hz code that joevt put up and poyda got working.

and put it in the right place

no extension or anything... have I missed some steps? there are no 50hz standard resolutions available in switchresX when I go back into that:

what have I done wrong?? please explain, if you would, as you would do to a small child, or your grandmother.

thanks in advance, L

Did you restart the computer?

Make sure no other files exist in the DisplayVendorID-4c2d folder (unless they have a different ProductID).

Make sure Finder preferences has "Show all filename extensions" selected and verify the file has no extension.

Make sure the format of the file is correct by right clicking it and selecting "Open in Property List Editor.app". Or you can type the following command in Terminal.app (it should say OK):

plutil /System/Library/Displays/Overrides/DisplayVendorID-4c2d/DisplayProductID-b80

You could verify the folder path is correct by using SwitchResX to create a timed resolution, type Command-S to save the timed resolution, and check that a file with the modification date of now exists in the DisplayVendorID-4c2d folder. Replace the file with the one you created and restart.