M1 Won't Wake External Monitor

I've finally had a breakthrough tonight with my 5K monitor that has a DisplayPort 1.4 (DP1.4) port for receiving 5K @60Hz.

To recap: this is a non-brand Chinese made 5K monitor that has an LG 5K panel (same one that's used in LG Ultra Fine 5K monitors and in 5K iMacs). This monitor has the following ports:

USB3 (DP1.2 only - 4K @60Hz maximum)

DP1.4 (5K @60Hz)

HDMI 1 (4K @60Hz) maximum

HDMI 2 (4K @60Hz) maximum

In the fall of 2020, I purchased an M1 MacBook Air and quickly discovered that the M1 MacBook Air could not even detect that an external monitor was connected when I was using the same TB3 to DP1.4 cable and the same DP1.4 port in the same monitor. So, not only could I not send an image from the M1 MacBook Air to this monitor, but the M1 MacBook Air wouldn't even detect that an external monitor was connected (as it was evident from the macOS System Information utility > Graphics/Display, i.e only the built-in display was detected by the M1 MacBook Air.

So, tonight it occurred to me that there was one adapter (of many, trust me), in my desk drawer that I've never tried. That was a TB3 to dual-DP1.2 adapter, which is meant to either connect two 4K monitors via DP1.2 (one monitor into each port on the adapter), or to connect both ports to a 5K capable display via two DP1.2 ports on the monitor to stitch two signals into one 5K @60Hz image. For that to work, the 5K display must be capable of receiving two DP1.2 signals (each signal via its own DP1.2 port on the monitor) and then internally stitch that image to make it 5K. That's an old technology (before DP1.4 standard was released) that was the only way for a monitor to display 5K without having to use Thunderbolt. With the release of DP1.4 standard, it became possible for a monitor to receive a 5K @60Hz signal via a single DP1.4 port. My Chinese-made no-brand monitor has the ability to receive a 5K @60Hz signal via one DP1.4 port, but it has no ability to stitch a 5K @60Hz signal from two DP1.2 signals. That was the reason I never opened that TB3 to dual-DP1.2 adapter.

So, to my great surprise, when I inserted the TB3 to dual-DP1.2 adapter between the M1-based Mac and my monitor connected one of the adapter's DP1.2 ports to the monitor's DP1.4 port with a DP1.4 to DP1.4 cable, my monitor came on instantaneously, and not only did it come on (for the first time) via its DP connector when connected to the M1-based Mac, but the signal was 5K @60Hz. Now, the most I could hope for the signal to be 4K @60Hz because both ports on the TB3 to dual-DP1.2 adapter are both DP1.2 ports, which are not capable of more than 4K @60Hz. But, strangely enough, the signal received by the no-brand Chinese-made monitor via its DP1.4 port was a genuine 5K @60Hz. Trust me, by now I know how to tell for sure. I've verified that the signal was in fact 5K @60Hz (both in the monitor menu utility and via the macOS System Information.

Now, I thought maybe the TB3 to the dual-DP1.2 adapter was mislabeled, and perhaps the ports on this adapter are not DP1.2 ports but DP1.4 ports. That would explain how my monitor is able to receive the 5K @60Hz signal from the M1-based MacBook Pro via this adapter. So, I pulled out my 13" 2020 MacBook Pro (Intel-based 10th generation CPU) and connected it to the same monitor via the same TB3 to dual-DP1.2 adapter, and guess what I found out? You will not believe it. The 13" 2020 MacBook Pro (Intel-based 10th generation CPU) was sending a 4K @60Hz to the monitor, just as I would have expected it to because the TB3 to dual-DP1.2 port adapter is not supposed to be able to send a 5K @60Hz toward the monitor out of a single one of its two DP1.2 ports (because the DP1.2 specification maxes out at 4K @60Hz).

So, I don't know exactly why this adapter solved my issue with the DP1.4-based 5K monitor, but it works perfectly. Moreover, the monitor wakes up as soon as I press a key on the external keyboard. There's no unpluggin/pluggin back and dancing with a tambourine around it for 5 minutes required. It works absolutely perfectly with the M1-based MacBook Air. The magic is in this TB3 to dual-DP1.2 adapter. My suspicion (and it's my suspicion only) is that Apple wired something wrong from the GPU in the M1-based Mac to the USB4 port. I actually suspect this is a hardware issue and not a software issue. Somehow, this TB3 to dual-DP1.2 adapter not only mitigate this incorrect wiring in the USB4 connector on the M1-based Mac but it also allows for the 5K @60Hz signal to be passed to the external DP1.4 based monitor out of the adapter's single DP1.2 port (which is not supposed to happen, and which is not happening with the Intel-based Macbook Pro).

For the rest of us, here's the information about the adapter that fixed the issue of DP1.4-based monitors not working with M1-based Macs:

Vendor: OWC (Other World Computing; aka MacSales.com)

Part Number: OWCTB3ADP2DP

Name: OWC Display Adapter Dual DisplayPort with Thunderbolt 3

Try waking with your mouse instead of your keyboard. I could not wake my M1 MacBook Air in clamshell mode attached to an external monitor with the keyboard as reported by others. Works flawlessly with the mouse. Press some buttons on your mouse and/or wiggle it a little. Works every time for me. HDMI connection.

Try to wake up the monitor with your mouse instead of your keyboard. That worked for me. Push the mouse buttons. Jiggle it around a little. Hope it works for you too. I have an LG monitor and an M1 MacBook Air.

I have this problem too. I use MBP M1 connect with external monitor Samsung S23C350 with Orico hub. But I noted that both monitor will dim down until black after 1 min (Battery Preference set up) an I can wake them both if the percentage of battery more than ~20%. If lower external monitor will won't wake. You have to plug the charger before wake them and you 've never face this problem whenever you're plugging.

Apple contacted you?? I'm having the same issue with M1 and is annoying as ****, I don't want to try every docking station or monitor if is something about Mac firmware update that needs to be fixed ASAP.

Far from ideal????? The Apple II E was 40 years ago. Apple has had 4 decades to get its act together. These things should work. I went through all the trouble you mentioned (for the umpteenth time), and my MacBook fell on my desk when putting it into the stand, damaging my desk. Totally unnecessary. 40 years...

Today is April 26, 2011. Apple has just released macOS 11.3 today. It has fixed my issues with the 5K display not being detected from the M1MacBook Air via DP1.4. Once I upgraded from 11.2.3 to 11.3, the 5K Display was detected via its DP1.4 port and a DP1.4 cable (USB3 male to DP1.4 male). The same cable didn't work with macOS 11.2.3, 11.2.2, 11.2.1, or any other previous version on macOS 11.x

Guys, I think i have a fix.

Disconnect everything from the USB C/HMDI adapter except your mac and hdmi cable to the monitor. No PD power in. No USB devices connected to the adapter. (Also first disconnect everything from the USB C adapter and wait 30 secs for it to completely reset.)

Since doing this, my mac will always wake up the monitor. No more opening the lid, unplugging/replugging (which did not always work anyways).

I still have the issue of waking up to the wrong resolution. But is is much easier to fix now that I can see the screen at least.

My setup is 1440p@60hz and retina. macOS 11.2.2. M1 Macbook. It has worked for over 1 week. I have not dared to change this setup. The second USB C port has a hub with the PD input and other USB devices.

I updated the macOS to 11.3, and my monitor issues have been resolved by this update.

My issue was with both the DP1.4 port on the monitor and with the HDMI port on the monitor. I haven’t tried HDMI after the update to macOS 11.3 because my monitor is 5K @60Hz, and the HDMI port on the monitor maxes out at 4K @60Hz, so there’s no point for me to use the HDMI port as long as the DP1.4 port works properly. But there’s a good chance that macOS 11.3 has fixed the HDMI issues as well.

Just get a direct USB-C to HDMI 2.0 cable. Something like this:

USB C to HDMI Cable for Home Office 6.6ft (4K@60Hz), Atvoiti USB Type C to HDMI Cable [Thunderbolt 3 Compatible] for Mac-Book Pro 2020/2019/2018, Pad Pro 2020, Galaxy S20, Surface Book 2 and More https://www.amazon.com/dp/B08P44HZKS/ref=cm_sw_r_cp_api_glt_fabc_0A11PVDDG45DXGDCA0E9?_encoding=UTF8&psc=1

USB-C to USB-C solved my problem (4 external monitors connected to Air M1):

https://forums.macrumors.com/threads/m1-macbook-closed-lid-dual-monitors.2269530/post-29650309

I got a call from Apple yesterday. They collected additional information on behalf of Engineering and then sent it back to Engineering.

The key for me was upgrading to 11.1 (from 11.0.1).

This addressed all issue of waking up, HDR color and resolution.

good, well so there are issues and I hope more driver updates wil come, hoping soon ;-)

Apple has been arrogant like this foe a while now. Probably over a decade. You be learned to deal with it and not expect much from Apple. Because the alternative is even worse.