m1 max failing to drive a single external display

[stevemiller]

My external monitor that was working fine with my previous 2018 MacBook Pro frequently glitches out and stops working with my 2021 model with 32 Core GPU and 32 gb ram.

I've tried multiple HDMI cables and the issue persists. Also I doubt its the cable or the display because as I said, as soon as I connect it to my old laptop or my work PC, it functions fine. I'm on the macOS 12.2 beta, but this also happened on the 12.1 official release as well as the shipping release on the machine when I first got it.

On a lark I googled this issue, and it appears the advice is to run the display at 30hz? This does in fact make the display start working again, but really!? There is no way this is an acceptable fix. Wondering if this a hardware issue I should get swapped? Though the fact that there are articles suggesting this fix for various M1 Macs makes me worried its a more widespread issue with Apple silicon.

 

[Sanpete]

What monitor?

 

[aevan]

My external monitor that was working fine with my previous 2018 MacBook Pro frequently glitches out and stops working with my 2021 model with 32 Core GPU and 32 gb ram.

I've tried multiple HDMI cables and the issue persists. Also I doubt its the cable or the display because as I said, as soon as I connect it to my old laptop or my work PC, it functions fine. I'm on the macOS 12.2 beta, but this also happened on the 12.1 official release as well as the shipping release on the machine when I first got it.

On a lark I googled this issue, and it appears the advice is to run the display at 30hz? This does in fact make the display start working again, but really!? There is no way this is an acceptable fix. Wondering if this a hardware issue I should get swapped? Though the fact that there are articles suggesting this fix for various M1 Macs makes me worried its a more widespread issue with Apple silicon.

My M1 Pro MBP runs external monitors or TVs over hdmi at 60hz, 4K, HDR with no issues. Could it be the cable? Or the port? Or the monitor?

 

[kentzh]

It’s very strange that I use HDMI to switch to MINI DP and connect to a 27-inch Apple LED Cinema Display, the computer will flicker and black screen when connected directly. On the contrary, I use the HDMI interface of the USB-C external docking station to switch, and the display is no problem. Very confused

 

[Fishrrman]

OP wrote:
"I've tried multiple HDMI cables and the issue persists. Also I doubt its the cable or the display because as I said, as soon as I connect it to my old laptop or my work PC, it functions fine."

Were any of the cables you tried verifiably "high speed HDMI 2.0" ??

Have you tried using a USBc (Mac) to displayport (display)?
or
USBc (Mac) to HDMI (display)?
or
USBc (Mac) to DVI (display)?
(assuming those ports available...)

 

[dwig]

Also, by "works fine" when mentioning the old Mac and the PC do you mean "works fine at 60Hz"?? Are those machines driving the monitor at 60Hz or at 30Hz??

 

[stevemiller]

Also, by "works fine" when mentioning the old Mac and the PC do you mean "works fine at 60Hz"?? Are those machines driving the monitor at 60Hz or at 30Hz??

previous machines definitely 60hz. also, the new machine sometimes drives it at 60, sometimes only at 30, sometimes it just suddenly goes to static. sometimes even the internal display only runs at 30 (or worse?).

I assume this can't be happening to everyone, but I'm also at a loss as to what do because the machine is so all over the place.

 

[stevemiller]

as an example of the many issues this machine has. the display corruption seems to happen when windows get resized to a particular size? eventually the whole thing became corrupted. also the irony of it being on this post of someone gushing about how well these machines handle external displays.... hrmph.