[erykwieliczko]

linux-aurora creates the HDMI/DisplayPort sound cards only when appledrm's hdmi_audio parameter is set, and it is off by default, so no Mac gets sound on an external display. This ships options appledrm hdmi_audio=1 in /usr/lib/modprobe.d, next to the notch default (asahi-notch.conf). The initramfs picks it up through modconf, as it does that one. An /etc/modprobe.d file with options appledrm hdmi_audio=0 turns it off again. The manual's hardware page says so in the same commit.

Testing

M3 Pro (J514S) with a TV on the HDMI port and on USB-C, running linux-aurora 7.2.11.aurora11 plus omacom/linux-aurora#295 and #297:

• the HDMI/DP sinks appear with the display;
• audio keeps playing across Chromium pause/resume and stream changes.

With alsa-ucm-conf-aurora at aurora-silicon/alsa-ucm-conf-asahi b9b2d0c82, the sinks also go away when the display is unplugged.

omarchy-mac/test: 17 of 20 scripts pass locally. setup, touchid-activate and touchid-consent fail the same way on unmodified main on this workstation (systemd-analyze verify: "Unit sysinit.target not found"), so they are left to CI.

Notes

• The parameter applies to every Mac, and this was tested only on the M3 Pro. Reports from M1/M2 owners with an HDMI or DisplayPort display are welcome.
• USB-C audio needs drm/apple: hold the audio link on the Type-C ports too linux-aurora#297. Without it, sound over USB-C stops after the first stream.

🤖 Generated with Claude Code

[greptile-apps]

Confidence Score: 4/5

[Medium impact] The default affects external-display audio across Macs using the package.

The PR appears safe to merge, with a small correction needed in the opt-out instructions.

Findings

1.  Display sound stays enabled ▶

Summary

Enables display sound by shipping options appledrm hdmi_audio=1 and adds an opt-out instruction to the hardware manual.

• HDMI and DisplayPort displays provide sound by default.

_{Reviews (1) · Last reviewed commit: "Turn on sound through HDMI and DisplayPo..." · Reviewed by Greptile}

[greptile-apps]

Display sound stays enabled

The opt-out instruction leaves out the filename. Files with different names in /etc/modprobe.d and /usr/lib/modprobe.d are read in filename order. For example, /etc/modprobe.d/00-local.conf containing options appledrm hdmi_audio=0 is followed by the shipped hdmi_audio=1, so sound stays enabled despite following the manual.

Tell readers to use /etc/modprobe.d/appledrm-hdmi-audio.conf, which replaces the same-named vendor file.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!