MP 6,1 LG 49wl95c Mojave 5120 x 1440 support

[plstrtfrd]

Enquiring for technically challenged friend, I'm doing all the support through FaceTime and Teamviewer

So... MacPro 6,1 D700 firmware all up to date, Mojave patched up.

Plug screen in through Thunderbolt (mDP) to DisplayPort, res is selectable but comes out janky.

5120 x 1440 is selectable at 60Hz and 30Hz. Both are bad. Select 3840 x 1080, obviously not great but it works.
According to write up on Everymac, Apple advised 3 x 5k displays can be connected through Thunderbolt ports.
(I've just realised it might be because the MacPro's only DP1.2, but surely the res option shouldn't even come up then?)

Tried two different DP 1.4 cables - same issue - selectable but janky.
Higher res not available through HDMI, 3840 is max. no issues.

Connect MBPro Mojave 10.14.6, via USB-C, works first time. No issues.

Used SwitchResX to look at EDID and compare between MB and MBP - everything's the same, no disparity between tables.

(Would try connecting MBP through CalDigit dock but he hasn't got a DP to DP cable.)

Friend isn't keen to go to Catalina as he's got a big mixing desk/studio set up with older kit that isn't Catalina compat.
Will be trying an external Catalina boot disk to see if that works.

I suppose at this stage, any comments welcome. (Upon reflection, it may well be the DP1.2 under Thunderbolt 2, but in my experience when the resolution isn't available you just can't select it)

Thx

 

[th0masp]

I vaguely recall a user in this forum at least two years ago who wanted to connect all those hi-dpi screens as advertised and found out you needed some really unusual DP-cable to pull that off - are there perhaps ones that are somehow actively powered and also plug into the USB port?

That might have been it.

 

[tpivette89]

Use multiple displays with your Mac Pro (Late 2013) - Apple Support

Learn how to connect multiple displays (such as monitors, TVs, and projectors) to your Mac Pro (Late 2013) using Thunderbolt, Mini DisplayPort, and HDMI connections.

support.apple.com

 

[joevt]

This is a problem with the drivers for the AMD graphics of the MacPro6,1. Complain to Apple.
5120x1440 is less pixels than 4K (3840x2160) so it only requires DisplayPort 1.2.

I guess support for 5K width is limited to dual link SST displays like the LG UltraFine 5K which uses two different DisplayPort 1.2 signals (one for the left half and one for the right half of the display). Intel GPUs prior to the 10th gen CPUs with Gen 11 graphics in the MacBook Pro 2020 and MacBook Air 2020 had a width limit of 4K in macOS (but 5K in Windows and Linux). Newer AMD GPUs have a width limit of 8K (higher for dual link SST displays I think - like 14K).

The output of the AGDCDiagnose command will give information about the connection, output resolution, and output pixel format:
/System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS/AGDCDiagnose -a > "AGDCDiagnoseMacPro6,1.txt" 2>&1

A recent version of Catalina (I don't know which version) added a hidden preference called enable5kUltrawideFix. I don't know what it does or what the default value is or what GPUs this affects. The following command will set the preference to true
sudo defaults write /Library/Preferences/com.apple.CoreDisplay enable5kUltrawideFix -bool true
The fix might refer to the issue with ultra wide displays with AMD graphics where you had to set DisplayPixelDimensions to 5120x1440 in the display override file to get 5120x1440 mode to be selectable (doesn't fix MacPro6,1 or old Intel GPUs).

 

[joevt]

5120x1440 seems to be working in the Big Sur beta for Kaby Lake graphics but not yet for Coffee Lake graphics. I don't know if MacPro6,1 AMD graphics is fixed.

 

[Pressure]

Should check out support for the Dell UP3218K.

 

[joevt]

Should check out support for the Dell UP3218K.

There are no new override files so I don't expect a behaviour change for the UP3218K. Overrides can be created in /Library/Displays/Contents/Resources/Overrides but displaypolicyd doesn't seem to read mtdd files from there. I can do a sudo cp my custom mtdd to /System/... in Big Sur (I though Big Sur was supposed to stop that?). displaypolicyd.stdout.log is not showing anything. I'm not sure if that's because there's no problems with my mtdd file. I still get the problem with my XV273K where the screen won't turn on when both cables are connected and an mtdd file exists.

 

[ascender]

Enquiring for technically challenged friend, I'm doing all the support through FaceTime and Teamviewer

So... MacPro 6,1 D700 firmware all up to date, Mojave patched up.

Plug screen in through Thunderbolt (mDP) to DisplayPort, res is selectable but comes out janky.

View attachment 921572

5120 x 1440 is selectable at 60Hz and 30Hz. Both are bad. Select 3840 x 1080, obviously not great but it works.
According to write up on Everymac, Apple advised 3 x 5k displays can be connected through Thunderbolt ports.
(I've just realised it might be because the MacPro's only DP1.2, but surely the res option shouldn't even come up then?)

Tried two different DP 1.4 cables - same issue - selectable but janky.
Higher res not available through HDMI, 3840 is max. no issues.

Connect MBPro Mojave 10.14.6, via USB-C, works first time. No issues.

Used SwitchResX to look at EDID and compare between MB and MBP - everything's the same, no disparity between tables.

(Would try connecting MBP through CalDigit dock but he hasn't got a DP to DP cable.)

Friend isn't keen to go to Catalina as he's got a big mixing desk/studio set up with older kit that isn't Catalina compat.
Will be trying an external Catalina boot disk to see if that works.

I suppose at this stage, any comments welcome. (Upon reflection, it may well be the DP1.2 under Thunderbolt 2, but in my experience when the resolution isn't available you just can't select it)

Thx

Were you able to get a resolution to this for your friend?

I’m just looking at the same issue with a Mac Pro and currently trying different cables & connectors - someone mentioned it needed to be an active mini-dp to dp cable?