[alsa-devel] RME MADIface 192 kHz problem

Florian Faber faber at faberman.de
Fri Oct 22 11:54:36 CEST 2010


>>>>> What is needed to get this card running at 192 kHz?
>>>> A working driver :)
>>>> http://wiki.linuxproaudio.org/index.php/Driver:hdspe
>>> How about posting the patches? :)
>> It would be dozens/hundreds of single patches against the hdspm driver.
> I don't mind any number of patches if they are written logically and
> well readable.
>> I'd rather replace it with the version above.
> If it's more or less compatible with the current driver, it's fine.
> But, one bulk patch is bad.  Even if you replace the driver code,
> split in a logical order, at best.

There are changes everywhere since the old driver inherited a lot of
code from the hdsp driver which in turn inherited a lot of code from
previous drivers. The code was never properly suited to support a
broader range of hardware.

I don't have the time to split up all the changes in all the different
places and if I had the time, I would rather do a complete rewrite (or
better: Finish the rewrite I started a while ago).

>> And I changed one ioctl
>> which would break compatibility - although I doubt anybody used the
>> levelmeter ioctl besides me. The version above is a 'public beta'.
> If it's a new ioctl, it's OK.  We can drop the old (very likely)
> unused ioctl eventually.  But using the same ioctl for different
> behavior is no go.

Ok, dropping the old one in favour of the new one.

>> If the support for the AIO/RayDAT finally works - sure. But for that I
>> still need to tell ALSA somehow that there are n buffers to use, n>2,
>> with n IRQs per buffer cycle.
> Well, actually I forget what your questions are.  Please continue it
> on ML here.
> All other sound drivers work fine with more than two periods, so I
> don't think there is any restriction in the API side.

Ok, the problem was that the AIO/RayDAT have two modes of operation, a
'windows' mode and a 'mac' mode. In the 'windows' mode the full 16k
sample buffer is utilized and the card produces 16k/period_size IRQs
while running through the buffer. I'd need a way to tell ALSA this.
In 'mac' mode it uses a double buffering scheme but only produces one
IRQ per each double buffer walkthru. I understand that ALSA does not
support this mode of operation.

Machines can do the work, so people have time to think.
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