Re: firewire mixer interface -- was Re: [PATCH 11/11] ALSA: digi00x: apply double-oh-three algorism to multiplex PCM samples

Clemens Ladisch
2015-03-20T14:07:58Z

Damien Zammit wrote:
> On 21/03/15 00:25, Takashi Sakamoto wrote:
>> Any userspace applications can destroy packet streaming which kernel
>> driver starts, by transaction to streaming-related register.
>>
>> In current implementation of ALSA firewire stack and Linux FireWire
>> subsystem, we cannot avoid this.
>
> Does that mean the mixer control will need root permissions to execute
> in userspace because the /dev/fwX node is usually owned by root?

/dev/fw* of audio devices typically get a different group to allow FFADO
to run. Whatever software implements these mixer controls (whether it
ends up called FFADO or not) would run with the same permissions.

Regards,
Clemens