I have an HDMI monitor on my Pi400 that defaults to standby when powered on.
Previously I had entries in config.txt to force HDMI audio - otherwise if I didn't get the monitor out of standby quick enough the OS would start up with no audio device (video was fine).
Since I've installed Trixie, this no longer works, because the hdmi_force* commands in config.txt are now obsolete (as are 99% of the 'how to force HDMI' topics on the internet).
By booting up with the monitor out of standby, I've been able to save the edid data from /sys/class/drm/card1-HDMI-A-1/edid, and I've updated /boot/firmware/cmdline.txt with drm.edid_firmware= pointing to the saved file.
I've tried renaming the edid file & rebooting which results in log messages indicating that the file wasn't found, thus confirming that when the file is correctly named it is being loaded.
However booting with the monitor in standby still results in no audio device.
Does anyone know how to force HDMI audio in Trixie if the monitor isn't present at bootup?
Just a note before anyone jumps in with the wrong answer - HDMI audio works 100% if the monitor is out of standby at boot time, I want a solution that will ensure HDMI audio works if the monitor is not detected at boot time.
Previously I had entries in config.txt to force HDMI audio - otherwise if I didn't get the monitor out of standby quick enough the OS would start up with no audio device (video was fine).
Since I've installed Trixie, this no longer works, because the hdmi_force* commands in config.txt are now obsolete (as are 99% of the 'how to force HDMI' topics on the internet).
By booting up with the monitor out of standby, I've been able to save the edid data from /sys/class/drm/card1-HDMI-A-1/edid, and I've updated /boot/firmware/cmdline.txt with drm.edid_firmware= pointing to the saved file.
I've tried renaming the edid file & rebooting which results in log messages indicating that the file wasn't found, thus confirming that when the file is correctly named it is being loaded.
However booting with the monitor in standby still results in no audio device.
Does anyone know how to force HDMI audio in Trixie if the monitor isn't present at bootup?
Just a note before anyone jumps in with the wrong answer - HDMI audio works 100% if the monitor is out of standby at boot time, I want a solution that will ensure HDMI audio works if the monitor is not detected at boot time.
Statistics: Posted by HiroProtagonist — Wed Dec 31, 2025 11:48 pm