[alsa-devel] Userspace control of HDA port connections

[Andrew Paprocki]

Takashi,

I'm wondering if there is any interest in providing a userspace way of
modifying the HDA port/mixer input/output mappings? The driver
currently uses hard-coded models to define the standard configuration
for a given piece of hardware, but this doesn't allow a user to
redefine a line-in port as an output port if the chipset has an
available unmapped mixer. I'm bringing this up because from what I
understand of the ALC883 is that it has 4 mixers, yet on my
motherboard there are only 3 ports configured as output by default
(6stack-dig). Correct me if I'm wrong, but I should be able to map all
of the physical jacks as outputs and then assign each of the mixers to
a jack or more than one jack. That would require adding a new model to
the driver and/or unloading/reloading the module with a new model
string. In a system which has the driver built-in and isn't using
modules, this requires a reboot. If there was a userspace way of
reconfiguring the jacks (via /proc/asound?) then perhaps even all of
the hardware -> model mappings could be moved into a little tool run
at boot time which doesn't require a kernel change every time new
hardware is introduced. A nice little ncurses tool could even be made
to modify port mappings. What do you think? If I'm misunderstanding
the capabilities of the chips please let me know.

Thanks,
-Andrew

p.s. I still have yet to test out the multi-card patch. I'll reply to
that once I have more info.