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Resolved 4k Display Confusion...

jlseattle

jlseattle

Cancelled
Jan 9, 2007
501
356
Seattle WA
That fixed it for me. It seems that I can get it work if I unplug the display, disconnect the power, and turn off the mac. Boot the macbook pro up and log in. Then plug in the display in. Then the right display settings (the icons selecting size versus the terrible drop down menu) are available. Hope this is fixed in the new OS version. I don't think this is a display hardware issue.
 
ascender

ascender

macrumors 601
Dec 8, 2005
4,961
2,852
I spoke too soon. The only semi-reliable way i've found to fix this without all the hassle of rebooting, unplugging etc is to use a displayport cable. And even then, there's no guarantee the resolution will stay if the machine goes to sleep.

My take is that its a combination of a few different things, but mainly usb-c ports/cables/config. There's been tales of similar behaviour (dongle/cable incompatibility and also wake-from-sleep issues) since these new MBPs were released. You only have to look at reviews on Amazon to see how bad it is with adapters working fine for one person and not for another, on the same laptops.

Its really frustrating.
 
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narcolpetic-haze

macrumors member
Feb 11, 2018
49
31
Speaking of LG monitors ...

I have the LG 27UD69-W 4K display, which apparently supports 4K 60Hz on the HDMI connections. I then bought the Belkin USB-C to HDMI (4k 60Hz) adaptor so I could connect my 2018 15" Macbook Pro, and have many short HDMI 2.0 compatible cables, yet I cannot for the life of me get anything over 30Hz.

Belkin says it's the monitor, LG just quoted me a line from the user manual where it mentions 4K 60Hz support. I know how to properly select resolutions and refresh rate on MacOS, so I'm a bit lost.. It can't even do 1080p at 60Hz.
 
ascender

ascender

macrumors 601
Dec 8, 2005
4,961
2,852
narcolpetic-haze said:
Speaking of LG monitors ...

I have the LG 27UD69-W 4K display, which apparently supports 4K 60Hz on the HDMI connections. I then bought the Belkin USB-C to HDMI (4k 60Hz) adaptor so I could connect my 2018 15" Macbook Pro, and have many short HDMI 2.0 compatible cables, yet I cannot for the life of me get anything over 30Hz.

Belkin says it's the monitor, LG just quoted me a line from the user manual where it mentions 4K 60Hz support. I know how to properly select resolutions and refresh rate on MacOS, so I'm a bit lost.. It can't even do 1080p at 60Hz.
Click to expand...

Have you tried it with Displayport? Just to check and narrow it down a bit?

HDMI 2.0 obviously supports 4K @ 60Hz, but you don't have to go far to find lots of really inconcistent experiences with usb-c and anything video/hub/dongle related unfortunately.
 
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narcolpetic-haze

macrumors member
Feb 11, 2018
49
31
ascender said:
Have you tried it with Displayport? Just to check and narrow it down a bit?
Click to expand...

Yeah, DisplayPort works (my Windows PC connects that way), but unfortunately I don't have any other way to test the HDMI.. oh well, guess I'll just cut my losses and get a USB-C to DP adaptor.
 
ascender

ascender

macrumors 601
Dec 8, 2005
4,961
2,852
I'm now in the to-be-expected loop of LG support saying I need to test the monitor with another usb-c Mac and/or test the Mac with another usb-c display. They've also recommended opening a ticket with Apple which I guess I can try, but I suspect their first step will be to ask the same.

I was hoping Mojave would fix the issue as i think its highly unlikely either the monitor or laptop are faulty. To me the symptoms appear to be a classic case of the sort of usb-c incompatibilities and inconsistencies which litter every usb-c product review on Amazon. i.e. hub/cable A works fine for half the customers and won't work for others with the exact same setup.
 
throAU

throAU

macrumors G3
Feb 13, 2012
8,878
7,034
Perth, Western Australia
sittingstill said:
Does anyone know what might cause the Retina mode "scaled resolutions" to not be available? I am connecting a 2015 15" Macbook Pro Retina to a 4k tv via HDMI, and the scaled resolutions do not appear, just "3840x2160 (low resolution)" and "1080p" (which is actually 1080p and not 2160p scaled to 'look like' 1080p). Option clicking provides additional non-native resolutions below 1080p, but the Retina scaling mode and "more / less / looks like" slider and options do not appear
Click to expand...

Your HDMI port might not support 4k (not all HDMI versions are the same, i think HDMI 1.4 or later is required for 4k, a 2015 machine's HDMI might not be that standard). And/or the cable might not support 4k

Try using display-port instead, or a mini-display-port to HDMI adapter cable (make sure the mdp-HDMI adapter has 4k support).

My Vega 64 GPU's HDMI won't do 4k on my 4k TV either. I got around it and got 4k to the TV out of it by using a displayport to HDMI 1.4 (or 2.0 i think, as i can get 50hz 4k on the TV which is higher than HDMI 1.4 spec) cable.
 
1

10below

macrumors newbie
Oct 15, 2018
1
0
tsyned said:
We just got an AOC U2777PQU 4k screen and had the issue where you could choose to scale from the drop down menu and set a resolution but you could not use the 4k res and have larger text with the nice retina sliding scale like on the iMac Pro main monitor. After many hours of looking through forums I noticed something on the Apple site about HDMI 1.4 support. On the new monitor, using its buttons, I changed the HDMI version from 2.0 to 1.4 and magically it now works PERFECTLY!
Click to expand...

I just bought the AOC myself and was going crazy staring at the tiny font size, was half thinking I needed to return it when a google search pointed me to this tip to switch to HDMI 1.4. Now it works like a charm! Thanks so much for pointing this out :) !!!
 
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narcolpetic-haze

macrumors member
Feb 11, 2018
49
31
ascender said:
I'm now in the to-be-expected loop of LG support saying I need to test the monitor with another usb-c Mac and/or test the Mac with another usb-c display. They've also recommended opening a ticket with Apple which I guess I can try, but I suspect their first step will be to ask the same.

I was hoping Mojave would fix the issue as i think its highly unlikely either the monitor or laptop are faulty. To me the symptoms appear to be a classic case of the sort of usb-c incompatibilities and inconsistencies which litter every usb-c product review on Amazon. i.e. hub/cable A works fine for half the customers and won't work for others with the exact same setup.
Click to expand...

Yeah I gave up trying to fix it. I tried 3 USB-C to HDMI adaptors rated at 4K 60Hz (2x expensive Belkin, 1x cheap Chinese generic), at least 4 different HDMI cables (1x supplied with the LG 4K 60Hz monitor, 3x from the shop I work at).

All I know for sure is the monitor does do 4K 60Hz via DP, so I guess I'll just buy one of those next.
 
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ascender

ascender

macrumors 601
Dec 8, 2005
4,961
2,852
4K 60Hz does work with DP, so I use that cable as well as a usb-c cable which sorts out power, speakers and the usb-a hub.

Only thing is that since Mojave, I sometimes have to reboot to get anything other than a black screen - the Mac recognises the display is connected, but there's no signal.
 
sittingstill

sittingstill

macrumors newbie
Jun 21, 2018
10
4
London, UK
throAU said:
Your HDMI port might not support 4k (not all HDMI versions are the same, i think HDMI 1.4 or later is required for 4k, a 2015 machine's HDMI might not be that standard). And/or the cable might not support 4k

Try using display-port instead, or a mini-display-port to HDMI adapter cable (make sure the mdp-HDMI adapter has 4k support).

My Vega 64 GPU's HDMI won't do 4k on my 4k TV either. I got around it and got 4k to the TV out of it by using a displayport to HDMI 1.4 (or 2.0 i think, as i can get 50hz 4k on the TV which is higher than HDMI 1.4 spec) cable.
Click to expand...

Well as I mentioned 2160p is available, just no 'retina mode' slider. I have been using this MacBook (with the same HDMI cable) for this purpose for 2 years....
 
R

rr_wolfpack

macrumors newbie
Dec 6, 2018
2
0
EugW said:
Does your HDMI adapter even support 4K?
Click to expand...
Thanks for your response. I'm using the HDMI cable that came in the box with the monitor. It says "High-Speed HDMI" on it. I'll check with a different HDMI cable. I hope it's HDMI cable issue.
 
EugW

EugW

macrumors G5
Jun 18, 2017
13,775
11,530
rr_wolfpack said:
Thanks for your response. I'm using the HDMI cable that came in the box with the monitor. It says "High-Speed HDMI" on it. I'll check with a different HDMI cable. I hope it's HDMI cable issue.
Click to expand...
Oh, I see you're using a 13" MacBook Pro early-2015, which has built-in HDMI. This is mainly a 12" MacBook thread, which requires an adapter to use HDMI. That's what I was asking about, but that doesn't apply to you.
 
AKmsk

AKmsk

macrumors newbie
Feb 14, 2019
1
0
I could’ve missed it but I haven’t seen anyone with mbp 15 late 2013. Shouldn’t I even try to connect it with 4k? Will it work?
 
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