Re: [FFADO-devel] [RFC][PATCH 0/3] ALSA: fireface: new driver for RME Fireface series (MIDI only)

[Jonathan Woithe <jwoithe@just42.net>]

On Sun, Dec 06, 2015 at 10:23:41PM +0900, Takashi Sakamoto wrote:
> Unfortunately, ffado library can disturb this functionality.
> In RME::Device::init_hardware() function, the library sends a write transaction
> to 0x0000801003f4 with invalid value as higher part of address in IEEE 1212 or
> ISO/IEC 13213. This is a worst case I describe in patch 03.

The number which FFADO writes to this register is not invalid: it is in fact
the same number which is used in drivers on other operating systems
(obtained from protocol analysis).

> I think it better that FFADO developers fixes the bug as long as they doesn't
> support MIDI functionality.

As above, this is not exactly a bug because other systems set that register
to the value which FFADO uses.  In the interests of interoperability I'm
willing to remove manipulation of this register from FFADO, but I suggest
that in time the ALSA driver should consider setting this register as is
done under other systems or else we could introduce subtle behavioural
differences down the track - at least until such time as we understand what
the high part of that register does.

jonathan