On Jan 05 Takashi Sakamoto wrote: [...]
This program just demonstrates how to use hwdep interface.
For Fireworks, via this interface, FFADO can use all of implemented commands without failures. And it's my solution for this ticket.
Here, I try to describe the detail related to this ticket[1]. I should have mentioned the detail in ffado-devel but I got the whole picture in the end of last year.
Cause: The bug is due to failure of some commands in some models. The commands are 'EfcGetClockCmd' and 'EfcPolledValuesCmd'. These commands are used to get device status. The bug appears in initializing process of FFADO. So this bug affects both streaming and mixer/control functionality.
[...]
In the end of last year, I had a contact in Echo Audio. I asked the implementation of 'Echo Fireworks Command/Response' over 'AV/C vendor dependent' command. The person answered that some commands are not implemented on current firmware for reported models. (I have no information for the reason.) The person also said that there are no differences between firmwares installed by drivers of Windows/OS X.
A solution: Using these addresses for command/response.
An issue: Using an address range for response has an issue. The address range is an exclusive-resource in an system [2].
In my opinion, considering ALSA/FFADO, it's better that such resource is used in kernel-land driver and the driver gives an interface to use it for user-land application.
Of cource, there is another way, to use this resource just in one user-land application such as ffado-dbus-server. Then I need to make another way for kernel-land driver. (Maybe implementing alternative AV/C commands)
[1] http://subversion.ffado.org/ticket/360 [2] http://mailman.alsa-project.org/pipermail/alsa-devel/2013-December/070447.ht...
Takashi and Clemens,
another alternative would be to implement sharing/multiplexing of the EFC response address range in firewire-core, like it is implemented for FCP_COMMAND and FCP_RESPONSE. Not sure if it is wise to share nonstandard address ranges though.