Re: [PATCH 0/3] ALSA: firewire-lib: preparation for media clock recovery

[Takashi Iwai <tiwai@suse.de>]

On Thu, 27 May 2021 14:26:08 +0200,
Takashi Sakamoto wrote:
> 
> Hi,
> 
> ALSA IEC 61883-1/6 packet streaming engine have been using pre-computed
> parameters ideal for nominal sampling transfer frequency (STF), to
> transfer packets to device since it was added 2011. As a result of user
> experience for a decade, it is clear that the sequence is not suitable
> to some actual devices.
> 
> In design of audio and music unit in IEEE 1394 bus, feedback of
> effective sampling transfer frequency is delivered by packets transferred
> from device. Reuse of the sequence of parameter in the packets results
> in pseudo media clock recovery to transfer packet.
> 
> In this patchset, an option is added to AMDTP domain so that each of
> AMDTP stream for outgoing packet has association to AMDTP stream for
> incoming packet, to replay the sequence of parameter. Some devices
> require receiving packet on-the-fly to transfer packets, so another
> option is added.
> 
> These options are just added, not used yet in this time. In future work,
> they are going to be used by drivers in ALSA firewire stack.
> 
> Takashi Sakamoto (3):
>   ALSA: firewire-lib: add replay target to cache sequence of packet
>   ALSA: firewire-lib: replay sequence of incoming packets for outgoing
>     packets
>   ALSA: firewire-lib: transfer rx packets on-the-fly when replaying

Applied all three patches now.  Thanks.


Takashi