[alsa-devel] [PATCH 0/2] ALSA: firewire-motu: add support for AudioExpress

[Takashi Iwai]

On Sun, 20 Aug 2017 14:25:02 +0200,
Takashi Sakamoto wrote:
> 
> Hi,
> 
> This patchset is to add support for MOTU AudioExpress. Any PCM frames and
> MIDI messages are transferred in rx/tx isochronous packets.
> Correspondingly, this adds an arrangement for specification flag for
> position of existence flag of MIDI messages.
> 
> I note that this unit has a quirk of acknowledge code against request
> subaction on asynchronous communication. In detail, please refer to 2nd
> patch of this set. To easy my development, I applied a patch to
> 'firewire-ohci' module on my develop ment tree. You can see the content in
> the end of this message. It's really a band-aid for the aim and can not be
> merged as what it is.
> 
> Unfortunately, current implementations of IEC 61883-1/6 packet streaming
> engine is not good enough in a point to presentation timestamp, as I
> reported[1]. Any plaback stream for the unit still causes periodical noise.
> 
> [1] [alsa-devel] Status of ALSA firewire stack at Linux v4.12 development period
> http://mailman.alsa-project.org/pipermail/alsa-devel/2017-April/120061.html
> 
> -------- 8< --------
> diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
> index 8bf89267dc25..06a0906a9b56 100644
> --- a/drivers/firewire/ohci.c
> +++ b/drivers/firewire/ohci.c
> @@ -1499,6 +1499,10 @@ static int handle_at_packet(struct context *context,
>                 packet->ack = evt - 0x10;
>                 break;
>  
> +       case 0x10:
> +               packet->ack = ACK_PENDING;
> +               break;
> +
>         case OHCI1394_evt_no_status:
>                 if (context->flushing) {
>                         packet->ack = RCODE_GENERATION;
> -------- 8< --------
> 
> 
> Takashi Sakamoto (2):
>   ALSA: firewire-motu: add specification flag for position of flag for
>     MIDI messages
>   ALSA: firewire-motu: add support for MOTU Audio Express

Applied both patches.  Thanks.


Takashi