[alsa-devel] PATCH - MIDI on ice1724 - real-time kernel problem SOLVED

Pavel Hofman pavel.hofman at insite.cz
Sun May 18 22:02:20 CEST 2008

Clemens Ladisch wrote:
> Pavel Hofman wrote:
>> Actually, when does the MPU_TX interrupt get thrown? Upon exhausting
>> some output buffer?
> According to the datasheet, when the number of bytes in the TX FIFO goes
> below the watermark value (for some unspecified value of "below").
> Is there a reason why the watermarks are set to 1 and not to 0?
> Anyway, this hardware is not compatible with the MPU-401, so we should
> not try to twist the MPU-401 code into working with it.  Please try the
> patch below (not tested, I don't have the hardware).


Thanks a lot. After a few pointer fixes to make it compile your code 
works flawlessly for both the generic as well as realtime ubuntu kernel.

I am enclosing the functioning patch.

Now I cannot feel any delay difference between usb and ice1724 midi 
inputs. Well done, gentlemen, thank you all.


Pavel Hofman.
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