Dne 20.2.2012 10:21, Jaroslav Kysela napsal(a):

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Clemens, thanks a lot for the information. How does it work when the alsa-lib chain contains plugins, such as plug, rate, etc.? I would assume the application circumvents these.

Nope. The mmap commit mechanism was introduced to keep the plugin interface functional. The direct mmap access to the DMA buffer is only applied for the direct hw: devices. If a plugin is used inside alsa-lib, the application talks to the plugin chain (it means that an intermediate buffer for samples can be allocated to let things working).

Jaroslav, thanks a lot for the clarification.

Pavel.