I decided to try and build something and add a 7" touchdisplay, specifically this model:
http://www.ingcool.com/wiki/7DP-CAPLCD
I’ve also been using an external DAC with no issues, TEAC UD-301.
However, when I have the display connected (both HDMI and USB for touchdisplay), the display works fine along with the touch but when I try and play audio to the external DAC, nothing happens. If I change the output audio to the HDMI or headphone, things are okay.
If I remove the 7" display and reboot, everything works again. Then if I plug in the display, things break again.
I have also tried to blacklist the bcm2835 so the only audio device that appears is the UD-301 but that doesn’t help either.
Here’s what aplay sees (after I allow the bcm2835 again so it’s no longer blacklisted, and it also looks the same if the 7" display is not plugged in):
card 0: b1 [bcm2835 HDMI 1], device 0: bcm2835 HDMI 1 [bcm2835 HDMI 1]
Subdevices: 4/4
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
card 1: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
Subdevices: 4/4
Subdevice #0: subdevice #0
Subdevice #1: subdevice #1
Subdevice #2: subdevice #2
Subdevice #3: subdevice #3
card 5: UD301 [TEAC UD-301], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
If I do a speaker test to 5,0 with the 7" plugged in:
Playback device is plughw:5,0
Stream parameters are 48000Hz, S16_LE, 1 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 32 to 262144
Period size range from 16 to 131072
Using max buffer size 262144
Periods = 4
Unable to set hw params for playback: Input/output error
Setting of hwparams failed: Input/output error
And without the 7" display:
Playback device is plughw:5,0
Stream parameters are 48000Hz, S16_LE, 1 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 32 to 262144
Period size range from 16 to 131072
Using max buffer size 262144
Periods = 4
was set period_size = 65536
was set buffer_size = 262144
0 - Front Left
There’s obviously a conflict with the 7" display but haven’t been able to find any solution to this or figure this out, any suggestions would be grateful!
Thanks,
Mike