Async USB Dac Experiments - testers wanted...

[MWelschenbach]

Is someone here who tried the kernels provided by Triode with Eximus DP1, or with any other USB audio class 2 dac?

[Triode]

Is someone here who tried the kernels provided by Triode with Eximus DP1, or with any other USB audio class 2 dac?

I don't think anyone has posted about tests using an audio class 2 dac yet - I'm awaiting with interest. [I was also holding off doing any more kernels until we got some feedback on this]

[MWelschenbach]

I don't think anyone has posted about tests using an audio class 2 dac yet - I'm awaiting with interest. [I was also holding off doing any more kernels until we got some feedback on this]

Since USB audio class 2 is specified as downward compatible to class 1 it should work, don't you think?

[Triode]

Since USB audio class 2 is specified as downward compatible to class 1 it should work, don't you think?

Well I think it would be useful to have some test cases. I don't think we have tried anything running as a high speed (480M) device yet. If the dac has a 1.1 full speed port then that will work, but I suspect this is not the case. In summary - I'm hopeful we can make it work, but at present with no test cases can't be sure.

[MWelschenbach]

Well I think it would be useful to have some test cases. I don't think we have tried anything running as a high speed (480M) device yet. If the dac has a 1.1 full speed port then that will work, but I suspect this is not the case. In summary - I'm hopeful we can make it work, but at present with no test cases can't be sure.

But again, the USB 2.0 high speed port is supposed to be downwards compatible to USB 1.1, so if the dac has a high speed USB port it should be able to operate the touch. However, some positive test cases to confirm this would be appreciated.

[Triode]

But again, the USB 2.0 high speed port is supposed to be downwards compatible to USB 1.1, so if the dac has a high speed USB port it should be able to operate the touch. However, some positive test cases to confirm this would be appreciated.

Its all under software control so will only be the case if the software supports this and works as intended... If the dac has a configuration to force it into 1.1 mode I would be reasonably confident it will work. If not and it "negotiates" to a lower rate then I am less confident. I think you would be the first person trialing it with a high speed device.

[MWelschenbach]

Its all under software control so will only be the case if the software supports this and works as intended... If the dac has a configuration to force it into 1.1 mode I would be reasonably confident it will work. If not and it "negotiates" to a lower rate then I am less confident. I think you would be the first person trialing it with a high speed device.

Well its a pity that I don't have a dac with high speed USB port, but I am interested in buying one - if it connects properly to the touch via USB.

[RadBadMark]

Triode - thanks for the effort from you and John with this!

I have a couple of DACs that are class 2 capable - I'll try and give it a test either tonight or over the weekend. Is there anything specific that I can feedback that would be particularly useful? Are you expecting them to run at high speed or fall back to full speed?

[Triode]

Triode - thanks for the effort from you and John with this!

I have a couple of DACs that are class 2 capable - I'll try and give it a test either tonight or over the weekend. Is there anything specific that I can feedback that would be particularly useful? Are you expecting them to run at high speed or fall back to full speed?

Do they work - and what the dmesg shows (when you ssh into touch and type dmesg). Most interesting if they don't work so we can try to get them to the point when they may.

[RadBadMark]

Asynchronous class 2 audio appears to be working well, although using your applet to change the soundcard doesn't work for me for some reason - when I select the USB DAC in the menu and the SBT reboots, it enters a continuous boot loop until I unplug the DAC, at which point it then boots normally and I can change it back to the default soundcard. To get round this I've selected the USB DAC by modifying asound.conf instead - I'm assuming this amounts to the same thing although I obviously don't have the the info from the app available. Can I get hold of this data elsewhere in the system?

I'm using test kernel 4 and it's been running in the background now for a couple of hours with no noticeable clicks, pops or dropouts. I'm not connected via a hub either, the DAC is bus powered and plugged straight into the back of the touch. Seems quite happy playing 44.1/48/88.2/96/176.4 & 192kHz off the server too, although I don't know what the SBT is doing internally. I should be able to verify output sample rates tomorrow as my other DAC has sample rate indicators

Hope this is useful!

Edit, found this..

# cat /proc/asound/card1/stream0
ARCAM ARCAM USB Audio 2.0 at usb-fsl-ehci.0-1, high speed : USB Audio

Playback:
Status: Running
Interface = 1
Altset = 1
URBs = 8 [ 8 8 8 8 8 8 8 8 ]
Packet Size = 1024
Momentary freq = 192010 Hz (0x18.0050)
Feedback Format = 16.16
Interface 1
Altset 1
Format: 0xa (32 bits)
Channels: 2
Endpoint: 1 OUT (ASYNC)
Rates: 44100, 48000, 88200, 96000, 176400, 192000
Data packet interval: 125 us
Max Packet Size = 1024
EP Attribute = 0x0