Oops, the subject line is truncated... It should be "ALSA: firewire-tascam: support notification of change of state for control surface". (My text editor works for the surplus.) On Fri, Nov 23, 2018 at 01:13:02PM +0900, Takashi Sakamoto wrote: > Hi, > > Units of TASCAM FireWire series transfer its state in tx isochronous > packets. The way to handle change of the state is a longstanding issue > since I firstly reveal the mechanism in this list[1]. > > In this time, Scott Bahling dedicates for further investigation to seek > better implementation[2][3][4]. Finally, we identified meaning of the > most of bits in the image of state, and decided which changes are worth > for userspace applications to handle as events. > > This commit adds support notification of the events. Userspace > applications can handle the notification via ALSA hwdep interface. > Furthermore, they can retrieve image of the latest states via the > interface. > > Changes from the initial proposal[5]: > - obsolete usage of mmap(2) due to several disadvantages. Instead, use > event queue for change notification, and add ioctl command to retrieve > image of states. > > Changes from the latest work[6]: > - To reduce time in an interrupt context in which tx isochronous packets > are handled, data in the event and the image is passed to userspace in > big-endian order. Additionally, image of the states are passed to > userspace in big-endian order as well. Userspace applications are > responsible to convert the data in host-endianness order. > - improve efficiency to copy batch of events to userspace in hwdep > interface > - rename structure and macro name. > > This patchset is also available in my remote branch for backport purpose > to Linux v4.17 or later[7]. > > I've already prepare userspace implementation; libhinwa. A > 'topic/firewire-tascam-pr' remote branch includes patchset for the > additional feature[8]. This library produces GObject class to handle the > event notification and emits GObject signal, and has a method > 'HinawaSndTscm.get_state()', with enough consideration to endianness. > Developers can process change of state with these two APIs. > > > Scott > > As the above, I changed method name from 'HinawaSndTscm.get_status()'. > I'd like you to change your local implementation for 'hinawa-utils'. > Sorry to add further work to you. > > [1] http://mailman.alsa-project.org/pipermail/alsa-devel/2015-July/094817.html > [2] http://mailman.alsa-project.org/pipermail/alsa-devel/2018-September/140051.html > [3] http://mailman.alsa-project.org/pipermail/alsa-devel/2018-October/140593.html > [4] http://mailman.alsa-project.org/pipermail/alsa-devel/2018-November/141395.html > [5] https://github.com/takaswie/snd-firewire-improve/tree/topic/tascam-userspace > [6] https://github.com/takaswie/snd-firewire-improve/tree/topic/tascam-userspace-take3 > [7] https://github.com/takaswie/snd-firewire-improve/tree/topic/tascam-userspace-pr > [8] https://github.com/takaswie/libhinawa/tree/topic/tascam-userspace-pr > > Regards > > Takashi Sakamoto (5): > ALSA: firewire-tascam: pick up data of state from tx isochronous > pakcets > ALSA: firewire-tascam: add new hwdep ioctl command to get state image > ALSA: firewire-tascam: queue events for change of control surface > ALSA: firewire-tascam: apply small refactoring to handle several type > of event for hwdep interface > ALSA: firewire-tascam: notify events of change of state for userspace > applications > > include/uapi/sound/firewire.h | 20 +++++ > sound/firewire/tascam/amdtp-tascam.c | 51 +++++++++++- > sound/firewire/tascam/tascam-hwdep.c | 115 +++++++++++++++++++++++---- > sound/firewire/tascam/tascam.h | 9 +++ > 4 files changed, 180 insertions(+), 15 deletions(-) > > -- > 2.19.1 > > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@xxxxxxxxxxxxxxxx > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
