[alsa-devel] include/uapi/firewire.h for other firewire drivers

Takashi Sakamoto o-takashi at sakamocchi.jp
Fri Oct 25 16:54:12 CEST 2013


Thanks for your quick reply.

> When a control panel wants to change several settings, it should not
> need to establish a CMP connection just to be able to prevent the driver
> from starting streaming at the same time.

There is no need to establish connection. The control panel just check 
the value of "peer-to-peer connection counter" field in iPCR/oPCR.

But anyway, it's better to give an easy way via the interface. I agree.

> When this is possible, the kernel FireWire framework should be extended
> to allow the driver to prevent FFADO from using the device.  However, it
> would be hard for the kernel to differentiate between FFADO and some
> control panel, so I guess FFADO should be changed to not attach to
> a device that already has a kernel driver.

I'm not a developer for Juju so cannot have any idea for kernel land at 
all. But for FFADO, I can put your idea as my future commitment.

> For Fireworks devices, applications will need to send EFC commands, but
> will not be able to allocate the same 0xecc080000000 address, so the
> driver needs a SEND_EFC ioctl.  (That's the same reason why snd-dice has

Now I understand the reason DICE_NOTIFICATION exists. Dice also have the 
similar issue as Fireworks has. For EFC, I'm willing to keep FFADO using 
"EFC over AVC" but I found this is not enough for some models with 
latest firmware.

Well, you said "The primary purpose is to support control panel/mixer". 
But this interface can also be good for prevention of conflict with 
FFADO driver. I wonder why you mention this first. Are there any thoughts?


Takashi Sakamoto

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