[AD] midi driver detection screws up digi driver detection

[Martijn Versteegh <m.versteegh@xxxxxxxxxx>]

Hi,

While doing some testing on tests/akaitest I found out that 

install_sound(DIGI_OSS, MIDI_AUTODETECT, NULL) 
will fail to install the OSS driver
while
install_sound(DIGI_OSS, MIDI_NONE, NULL) 
succeeds. I did some tracing and this is what happens:

-The OSS driver is detected succesfully. 
-The ALSA rawmidi driver is detected. 
-The digi driver is installed succesfully
-The midi driver fails to install.
-install sound fails

The annoying thing is that when I run the second line once,
the first one will succeed as well until I reboot the machine.

If I have time I'll try to patch up install sound a bit. I propose:
1) install sound should fail if you explicitly specify a
driver which isn't detected. Right now it'll do autodetection if it fails
on the explicitly specified driver, giving you another driver than you 
expect. Maybe it should switch to digi/midi_none and never fail?
2) if something goes wrong in installing one of digi_driver/midi_driver
this should not screw up the installation of the other one. This means
that at 1) it should probably switch to the *_none driver and never fail.

-- 

Martijn Versteegh