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

[Takashi Sakamoto <o-takashi@sakamocchi.jp>]

Hi,

On Dec 07 2015 06:57, Jonathan Woithe wrote:
> 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).

No.

As long as I tested with a debug option to firewire-ohci module, it 
sends write transaction with '01000000'. This value includes invalid 
node ID.

ConfigRom::getNodeId() returns the invalid value. I think there's 
something wrong coding, such like forgetting initialization or update of 
the instance.

>> 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.


Regards

Takashi Sakamoto