Boot process hangs when HDMI cable is connected

[HarmenJorritsma]

Hi!

When HDMI cable is connected during boot process, the boot process hangs and throws a apple dcp (something with turn on...) message on a black screen. Whithout HDMI cable the boot process succeeds.

It is very remarkable that when HDMI cable is connected after boot process (when OS is running), HDMI connection works fine!

Any suggestions to solve this issue? It is very annoying to unplug and plug the HDMI cable every start up process.

Kind regards,

Harmen

[tobhe]

thanks for the info, that is very good to know in case people report similar issues in the future! The next upstream Asahi kernel update apparently comes with a bunch of HDMI improvements, there is a fair chance it also fixes this.

I'll let you know when we have a version to test but it might take a while.

[eslerm]

Just to add, there are a few related bugs: AsahiLinux/asahi-installer#251

[devnoname120]

Interestingly I don't have this issue at all on my Mac mini (M1, 2020) running Ubuntu Server 22.04.4 LTS (5.19.5-10-asahi).

Edit: do you mean connected before booting the computer or only connecting HDMI during the booting process? I assumed the former.

[tobhe]

I can confirm that there is not issue on my M1 mini 22.04, 23.10 and 24.04 so this seems to only affect laptops with HDMI ports. 24.04 ships with a 6.8 kernel, it would be worth checking if that fixes your issue.

[wez]

I'm also hitting this; I have a mac studio m2 ultra and only have HDMI display devices that can be attached (actually, a pikvm). I actually want to run this headless, but I don't know how to get ssh enabled without being able to see what comes up. I would greatly appreciate suggestions on how to get past this, as I do not want to use Fedora on this machine.

[wez]

To clarify what I see, sometimes I see just this:

sometimes I see the ubuntu logo and spinner wheel, but stopped.

I tried leaving hdmi disconnected for a while before connecting it, but I'm not able to see anything useful; to all appearances the system has hung, although I can ping the IP that I see my router assign to it.

If there's a way to persuade the system to come up with sshd and let me login, I can probably fix things up from here. I've never gotten past this point, so I don't know what the system even looks like.

[wez]

My workaround for this was to install qemu on the macos side, start an ubuntu vm there, mount the physical linux disk, chroot into it, install sshd, set a password, then reboot with the hdmi unplugged. I'm now currently ssh'd in and running a dist upgrade and will see if that allows me to boot with the hdmi cable attached in the future.

[wez]

I can confirm that 24.04 LTS resolves this issue. It would be great for the installer image to be updated to this release, as it was a bit of an ordeal to get a usable system!