On Wed, 02 May 2018 12:16:38 +0200, Takashi Sakamoto wrote:
Hi,
This patchset updates my previous one:
[alsa-devel] [PATCH v2 00/11] ALSA: dice: use cache of stream formats to generate PCM rules/constraints http://mailman.alsa-project.org/pipermail/alsa-devel/2018-April/135330.html
Once, ALSA dice driver cached stream formats to generate PCM constraints/rules. The cache is created by changing current sampling transmission frequency step by step directly at unit probing process. This feature was dropped because it changes state of clock on target device thus it's against users' expectation[1].
However this is not necessarily convenient because reconfiguration of sampling rate is not available.
TC Applied Technologies (TCAT) has extended protocol for DICE interface, a.k.a EAP (Extended Application Protocol). In this extension, drivers can retrieve information of stream formats without changing state of target unit. Fortunately, this protocol is supported widely by many models.
This patchset regain the cache to generate PCM constraints/rules by using this protocol. Userspace applications can reconfigure sampling rate via ALSA PCM interface.
For units which doesn't support the extension, available set of sampling rate is still restricted at current sampling transmission frequency. This is also inconvenient and this patchset introduces a solution.
Structure for unit entry (struct ieee1394_device_id) has a member for unit-specific data. This patchset uses it for callback function to handle hard-coded stream format. In this time, I adopt this way for some known models produced by TC Electronic and Alesis. If users find their models still have restrictions in a point of available sampling transmission frequency, it's preferable to work for this way.
Changes from v2:
- use robust representation to calcurate mode of sampling transmission frequency.
[1] [alsa-devel] [PATCH 0/6 v2] ALSA: dice: constrain PCM substreams to current sampling transfer frequency http://mailman.alsa-project.org/pipermail/alsa-devel/2016-February/104065.ht...
Takashi Sakamoto (13): ALSA: dice: add cache of stream formats ALSA: dice: add 'firewire' directory for proc nodes ALSA: dice: add proc node for stream formation ALSA: dice: cache stream formats at current mode of sampling transmission frequency ALSA: dice: add parameters of stream formats for models produced by TC Electronic ALSA: dice: add parameters of stream formats for models produced by Alesis ALSA: dice: use extended protocol to detect available stream formats ALSA: dice: use cache of stream format to check running stream ALSA: dice: add a helper function to restart all of available streams ALSA: dice: enable to change current sampling transmission frequency ALSA: dice: use stream formats to add MIDI substreams ALSA: dice: use cache for PCM constraints and rules ALSA: dice: remove local frag of force_two_pcms
Applied all patches now. Thanks.
Takashi