# means a comment. All such lines are ignored.
camera_auto_detect, display_auto_detect, etc are all configuration options, which take either integer or string values depending on the option.
dtparam and dtoverlay are directives to manipulate device tree, either as a parameter or overlay.
You're not saying "dtparam=on", but process "audio=on" or similar as a dtparam command. (There are also dtparam and dtoverlay commands in Linux to dynamically apply DT changes - https://www.raspberrypi.com/documentati ... #part3.5.1).
AIUI In DT, absent, on, and 1 are normally synonyms.
Likewise off and 0 are synonyms.
This is largely covered by https://www.raspberrypi.com/documentati ... ml#part3.1, although there are a couple of bits that make some assumptions about knowing about DT.
https://www.raspberrypi.com/documentati ... ml#part2.2 goes into more detail with regard what you're actually doing.
"dtparam=audio=on" is enabling the line at https://github.com/raspberrypi/linux/bl ... b.dts#L497so the kernel command line gains all those properties. The main one that is actually desired is "snd_bcm2835.enable_headphones=1" to tell it to enable the headphone output. The fact that this one is using a lookup table for the two states means I don't know for certain whether =1 will work.
camera_auto_detect, display_auto_detect, etc are all configuration options, which take either integer or string values depending on the option.
dtparam and dtoverlay are directives to manipulate device tree, either as a parameter or overlay.
You're not saying "dtparam=on", but process "audio=on" or similar as a dtparam command. (There are also dtparam and dtoverlay commands in Linux to dynamically apply DT changes - https://www.raspberrypi.com/documentati ... #part3.5.1).
AIUI In DT, absent, on, and 1 are normally synonyms.
Likewise off and 0 are synonyms.
This is largely covered by https://www.raspberrypi.com/documentati ... ml#part3.1, although there are a couple of bits that make some assumptions about knowing about DT.
https://www.raspberrypi.com/documentati ... ml#part2.2 goes into more detail with regard what you're actually doing.
"dtparam=audio=on" is enabling the line at https://github.com/raspberrypi/linux/bl ... b.dts#L497
Code:
audio = <&chosen>,"bootargs{on='snd_bcm2835.enable_headphones=1 snd_bcm2835.enable_hdmi=1',off='snd_bcm2835.enable_headphones=0 snd_bcm2835.enable_hdmi=0'}";Statistics: Posted by 6by9 — Wed Apr 16, 2025 2:47 pm