Difference between revisions of "Research Pre Audio"
Jump to navigation
Jump to search
(start audio research page) |
(add script to strace audiod) |
||
| (4 intermediate revisions by one other user not shown) | |||
| Line 1: | Line 1: | ||
This side should cover the audio architecture used on the Palm Pre. | This side should cover the audio architecture used on the Palm Pre. | ||
| + | |||
| + | == Hardware == | ||
| + | |||
| + | The used TWL4030 PMIC covers the audio part. | ||
| + | TODO: datasheet available? | ||
== Soundcards == | == Soundcards == | ||
| − | |||
<pre> | <pre> | ||
root@castle:/var/home/root# aplay -l | root@castle:/var/home/root# aplay -l | ||
| Line 12: | Line 16: | ||
Subdevices: 1/1 | Subdevices: 1/1 | ||
Subdevice #0: subdevice #0 | Subdevice #0: subdevice #0 | ||
| + | </pre> | ||
| + | |||
| + | == Scripts == | ||
| + | |||
| + | Palm uses scripts to configure the lower levels of the sound system that are executed inside the kernel. Audiod triggers them over a sysfs interface. | ||
| + | <pre> | ||
| + | echo "#list" > /sys/devices/platform/twl4030_audio/scdebug | ||
| + | </pre> | ||
| + | for example lists you all available scripts over the kernel message output which you can view with dmesg. You can also try | ||
| + | |||
| + | <pre> | ||
| + | #all | ||
| + | #volume | ||
| + | #init | ||
| + | </pre> | ||
| + | |||
| + | These scripts can be triggered by writing is name as a string into | ||
| + | |||
| + | <pre> | ||
| + | /sys/devices/platform/twl4030_audio/scrun | ||
| + | </pre> | ||
| + | |||
| + | A good start to dive into this is sound/arm/omap-twl4030/script.c in the kernel patch from palm. | ||
| + | |||
| + | New scripts are inserted into the kernel list via: | ||
| + | |||
| + | <pre> | ||
| + | /sys/devices/platform/twl4030_audio/scinit | ||
| + | </pre> | ||
| + | |||
| + | This is also handled by audiod. The scripts can be found in /etc/audio | ||
| + | |||
| + | == strace audiod == | ||
| + | this script restarts the audiod with an attached strace which is saved in ./audio.log: | ||
| + | |||
| + | <pre> | ||
| + | #!/bin/sh | ||
| + | #Make sure audiod gets not restarted when we kill it | ||
| + | mv /usr/sbin/audiod /usr/sbin/audiod-backup | ||
| + | kill $(pidof audiod) | ||
| + | |||
| + | sleep 2 | ||
| + | |||
| + | strace -x -s 10000 -f -F -o audio.log audiod-backup & | ||
| + | echo "press any key to return to normal mode" | ||
| + | read foo | ||
| + | kill $(pidof audiod-backup) | ||
| + | |||
| + | sleep 2 | ||
| + | |||
| + | #Bring the system into a useable state again | ||
| + | mv /usr/sbin/audiod-backup /usr/sbin/audiod | ||
| + | sh /etc/event.d/audiod | ||
| + | |||
| + | |||
</pre> | </pre> | ||
Latest revision as of 22:17, 29 March 2010
This side should cover the audio architecture used on the Palm Pre.
Hardware
The used TWL4030 PMIC covers the audio part. TODO: datasheet available?
Soundcards
root@castle:/var/home/root# aplay -l **** List of PLAYBACK Hardware Devices **** card 0: mcbsp2 [twl4030-i2s (mcbsp2)], device 0: omap-mcbsp-pcm [omap-mcbsp-pcm] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: mcbsp3 [btsco (mcbsp3)], device 0: omap-mcbsp-pcm [omap-mcbsp-pcm] Subdevices: 1/1 Subdevice #0: subdevice #0
Scripts
Palm uses scripts to configure the lower levels of the sound system that are executed inside the kernel. Audiod triggers them over a sysfs interface.
echo "#list" > /sys/devices/platform/twl4030_audio/scdebug
for example lists you all available scripts over the kernel message output which you can view with dmesg. You can also try
#all #volume #init
These scripts can be triggered by writing is name as a string into
/sys/devices/platform/twl4030_audio/scrun
A good start to dive into this is sound/arm/omap-twl4030/script.c in the kernel patch from palm.
New scripts are inserted into the kernel list via:
/sys/devices/platform/twl4030_audio/scinit
This is also handled by audiod. The scripts can be found in /etc/audio
strace audiod
this script restarts the audiod with an attached strace which is saved in ./audio.log:
#!/bin/sh #Make sure audiod gets not restarted when we kill it mv /usr/sbin/audiod /usr/sbin/audiod-backup kill $(pidof audiod) sleep 2 strace -x -s 10000 -f -F -o audio.log audiod-backup & echo "press any key to return to normal mode" read foo kill $(pidof audiod-backup) sleep 2 #Bring the system into a useable state again mv /usr/sbin/audiod-backup /usr/sbin/audiod sh /etc/event.d/audiod