[alsa-devel] [PATCH 00/10] ALSA: firewire-motu: reserve/release isochronous resources in pcm.hw_params/hw_free callbacks

[Takashi Iwai]

On Mon, 17 Jun 2019 10:15:00 +0200,
Takashi Sakamoto wrote:
> 
> Hi,
> 
> This patchset is the last part of patches for all of drivers in ALSA
> firewire stack to reserve/release isochronous resources in
> pcm.hw_params/hw_free callbacks, like the other patchsets:
> 
> https://mailman.alsa-project.org/pipermail/alsa-devel/2019-June/150118.html
> https://mailman.alsa-project.org/pipermail/alsa-devel/2019-June/150863.html
> 
> In current implementation, the resources are reserved at the same time
> to start packet streaming, and released at the same time to stop packet
> streaming. However, once allocated, the resources are available
> independent of lifetime of each of packet streaming.
> 
> The isochronous resources are the resources of IEEE 1394 bus. On the
> other side of view, it's a kind of resources of hardware to maintain
> the bus (isochronous resource manager). For this kind of reservation and
> release, hw_params and hw_free operations are suitable in ALSA PCM
> interface.
> 
> Ideally, the operation to reserve/release isochronous resource should
> be separated from the operation to start/stop packet streaming. However,
> IEEE 1394 bus has reset event. Once reset occurs, isochronous resource
> manager releases allocated resources. The resources should be
> reallocated by requesters themselves. For this reason, in this patchset,
> bus generation is checked before starting packet streaming. If
> generation is updated, reallocation is requested to isochronous
> resource manager, then packet streaming starts.
> 
> Takashi Sakamoto (10):
>   ALSA: firewire-motu: unify the count of subscriber for packet
>     streaming
>   ALSA: firewire-motu: unify midi callback function
>   ALSA: firewire-motu: add helper function to keep isochronous resources
>   ALSA: firewire-motu: code refactoring for condition to stop streaming
>   ALSA: firewire-motu: rename helper functions to begin/finish streaming
>     session
>   ALSA: firewire-motu: minor code refactoring to stop isochronous
>     context
>   ALSA: firewire-motu: code refactoring to finish streaming session
>   ALSA: firewire-motu: reserve/release isochronous resources in
>     pcm.hw_params/hw_free callbacks
>   ALSA: firewire-motu: update isochronous resources when starting packet
>     streaming after bus-reset
>   ALSA: firewire-motu: code refactoring for pcm.hw_params/hw_free
>     callbacks

Applied all ten patches now.  Thanks.


Takashi