Dual Monitor Setup crashing Monterey

it didn't help me

Sounds promising. So you're using a USB-C to DisplayPort cable?

MacOS did make some changes in the area of power management for multiple displays for Monterey.

What is the setting of Low power Vs High power when this happens?

If you change that setting, does the problem change in any way?

Use High Power Mode on your 16-inch MacBook Pro with M1 Max - Apple Support

.

Updating this for everyone else with final solutions:

My Intel-Based MBP 16" 2019 has two SMK Link USB-C hubs https://www.smklink.com/products/usb-c-multi-port-hub (rated for 4K but web site does not talk about refresh rate), used to connect to 2 Samsung u32H85x 4K monitors via Monoprice 4K High Speed HDMI cables https://www.monoprice.com/product?p_id=2529 rated 4K@60hz.

In this original configuration, external monitors show 30hz as the max available resolution, so I am assuming SMK Link USB-C is max rated 4k @30hz. With Internal panel 4K@60hz + 2 external monitor 4K@30hz connected via SMK Link USB-C hubs -> Idle timeout -> Wake from idle leads to hard crash.

Solution 1:

Lowering internal panel to any value less than 4k@60hz (48, 50, 59.95hz) and leaving external monitors 4K@30hz makes the crash on idle resume go away.

Solution 2:

Based on my company's tech support engineer suggestion, I bought 2 USB C to HDMI Cable for Home Office 6ft (4K@60Hz), uni https://www.amazon.com/dp/B075V5JK36?ref=ppx_yo2_dt_b_product_details&th=1 rated 4K@60Hz. I discarded two USB-C from two right ports and plugged in monitors directly via cables. The monitors now showed 60hz as max refresh rate, quite lovely.

In this configuration, everything works well:

Internal panel 4K@60hz + 2 external monitor 4K@30hz connected directly with USB-C to HDMI cable works.

Internal panel 4K@30hz + 2 external monitor 4K@30hz connected directly with USB-C to HDMI cable works.

Internal panel 4K@60hz + 2 external monitor 4K@60hz connected directly with USB-C to HDMI cable works.

Hope this helps anyone else having this issue.

if we apply classical debugging analysis, and look at the problem following what Hardware, you haver determined that for your setup, the ADAPTERS you had failed when in place, worked when those adapters were replaced with known-good ones of another type.

As I read it, based on your experience the take-away is:

Adapter users beware! your display adapters could cause mysterious crashes.

Just FYI, I coincidentally already have those UNI brand USB-C to HDMI cables and I have this same freeze problem using them with two Samsung 4k monitors on my 2019 MB Pro 16." You stand a high chance of seeing the freeze again, and I would not recommend this as a fix if someone is looking to purchase them as a fix.

This setup has worked flawlessly, crash free for me for close to 18 months before the upgrade to Monterey - there is very clearly a device driver issue here, it is NOT hardware related.

I am trying the workaround to lower the Hz on the MacBook display itself. I will see how that goes. Of note, I changed my MacBook display to 50hz and then reconnected my second 4k monitor again. I had the freeze up within 5 minutes, because I noticed that the act of connecting the second monitor set the MacBook display back to 60Hz again. Make sure you check the MacBook display immediately after the 2 monitors are connected.

I solved this problem by replacing 1 cable. usb with - hdmi to usb with - displayport. after that, everything works. The second cable left usb with - hdmi. Я решил эту проблему, заменив 1 кабель. usb с - hdmi к usb с - порт дисплея. после этого все работает. Второй кабель оставил usb с - hdmi

I've had a very similar issue to this, that immediately started on upgrading to Monterey. LG 4K UHD 27UN83A – worked perfectly via USB-C, then crashed WindowServer straight after the update.

Symptoms were returning to the login screen and asking for password over and over in an endless loop. Only unplugging the cable stopped it. HDMI + adapter was fine, as was the original USB-C in Safe Mode.

The fix I found...

• Deleted com.apple.windowserver.plist from the Preferences / ByHost folder
• Went into Safe Mode and checked the monitor worked. Returned scaling to default, and set Frame Rate to 30.
• ON THE LG MONITOR, changed DisplayPort Version from 1.4 to 1.2 in General Settings.

The first two I had tried before, so it's likely the monitor setting was the crucial element. Afterwards I rebooted and everything worked as it did on Big Sur, and was able to change scaling and frame rate back.

Hopefully this helps someone else.

Refresh rate 50hz works too. Retrying next with 59.94 hertz...

I confirm that setting main display to 48, 50, 59.95hz makes the crash go away. Main screen @ 60hz + 2 4K monitors at 30hz == crash.