[Ardour-Dev] Alsa works, Ardour/Jack fails

[Patrick Shirkey]

Mike Mazarick wrote:
>
> I’m into a rather unusual problem, and would like a pointer towards 
> how to diagnose the issue further.
>
> I have 4 soundcards with 8 channels each (drivers are not in the Alsa 
> tree yet), which are sync’d together to behave as one sound card.
>
> The interrupts on all but the master are disabled.
>
> I can clearly play sound with aplay on all 32 channels.
>
> However, when I play the 4 cards using qjackctl and ardour2, I get 
> distortion on the first 24 channels, and only static/white noise on 
> the last 8. The last 8 channels sound like a bad guitar cord that is 
> being wiggled around.
>
> Has anyone run into anything similar to this? The driver writes to the 
> /var/log/messages file, and everything looks good there, and also 
> looks good in Jack (no XRUNS, etc). If you have a clean ‘divide and 
> conquer’ idea, I’m all ears.
>

This may be related to volume levels? Have you tried adjusting the 
output of ardour or the alsamixer settings?

Also, have you tried using another jack app to playback audio to each 
channel like alsaplayer for example?

What you are doing with 4 synced sound cards is fairly unusual and if 
you are using alsa dmix to run them as one card there could well be some 
outstanding bugs in the driver You could also try running them in sync 
with netjack.

Are you using the plughw interface?



Cheers.






> TIA,
>
> Mike Mazarick
>
> Here’s and example of the /var/log/messages file (while setup for 512 
> frames/period and 4 periods/buffer in qjackctl):
>
> …
>
> Jan 12 22:18:04 localhost kernel: pci_gl824_probe vendor=0x10b5 
> device=0x2108 subvendor=0x2020 subdevice=0x840
>
> Jan 12 22:18:04 localhost kernel: pci_gl824_probe vendor=0x10b5 
> device=0x2108 subvendor=0x2020 subdevice=0x840
>
> Jan 12 22:18:04 localhost kernel: ACPI: PCI Interrupt 0000:05:00.0[A] 
> -> GSI 16 (level, low) -> IRQ 16
>
> Jan 12 22:18:04 localhost kernel: api_gl824_request_card index 0
>
> Jan 12 22:18:04 localhost kernel: api_gl824_map_regions
>
> Jan 12 22:18:04 localhost kernel: uart_gl824_initialize
>
> …
>
> Jan 12 22:18:09 localhost kernel: pld_gl824_disable_audio_interrupts
>
> Jan 12 22:18:09 localhost kernel:last message repeated 3 times
>
> Jan 12 22:18:09 localhost kernel: api_gl824_find_input_clocks 1 ---> 0
>
> Jan 12 22:18:09 localhost kernel: api_gl824_find_input_clocks 3 ---> 1
>
> Jan 12 22:18:09 localhost kernel: api_gl824_find_input_clocks 2 ---> 3
>
> Jan 12 22:18:09 localhost kernel: api_gl824_find_input_clocks card 3 
> is a master, enabling interrupts for it
>
> Jan 12 22:18:09 localhost kernel: pld_gl824_enable_audio_interrupts
>
> …
>
> Jan 12 22:19:34 localhost kernel: pcm_gl824_output_prepare Attempting 
> to allocate 32 channels GL mode N32
>
> Jan 12 22:19:34 localhost kernel: pcm_gl824_output_prepare Card 
> channels 0..31 allocated to substream
>
> Jan 12 22:19:34 localhost kernel: pcm_gl824_output_trigger 1
>
> Jan 12 22:22:54 localhost kernel: pcm_gl824_output_trigger 0
>
> Jan 12 22:22:54 localhost kernel: api_gl824_stop Master card's clock 
> position stopped at 1
>
> Jan 12 22:22:54 localhost kernel: api_gl824_stop Slave card's clock 
> position stopped at 1
>
> Jan 12 22:22:54 localhost kernel:last message repeated 2 times
>
> Jan 12 22:22:54 localhost kernel: api_gl824_stop ISR took between 181 
> and 272 samples
>
> Jan 12 22:22:54 localhost kernel: api_gl824_stop Buffer transfers TO 
> CARD within ISR took between 180 and 271 samples
>
> Jan 12 22:22:54 localhost kernel: api_gl824_stop Buffer transfers FROM 
> CARD within ISR took between 0 and 1 samples
>
> Jan 12 22:22:54 localhost kernel: pcm_gl824_output_hw_free
>
> Jan 12 22:22:54 localhost kernel: pcm_gl824_output_hw_free
>
> Jan 12 22:22:54 localhost kernel: pcm_gl824_output_close
>
> ------------------------------------------------------------------------
>
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>   


-- 
Patrick Shirkey
Boost Hardware Ltd.