[alsa-devel] Direct use of the DMA buffer?
Hello,
Please excuse my ignorance, but is it possible for an application to directly use/output to the DMA buffer allocated by the kernel in hw_params? Something like using the actual DMA buffer in the snd_pcm_writei function, without copying the data in alsa-lib/driver PCM midle layer (?), just managing the pointers.
Only a theoretical question though, no plans on my side :)
Thanks a lot for even a short No :-)
Best regards,
Pavel.
Pavel Hofman wrote:
Please excuse my ignorance, but is it possible for an application to directly use/output to the DMA buffer allocated by the kernel in hw_params?
Set one of the SND_PCM_ACCESS_MMAP_* access types and then use snd_pcm_mmap_begin/commit.
Regards, Clemens
Dne 20.2.2012 09:11, Clemens Ladisch napsal(a):
Pavel Hofman wrote:
Please excuse my ignorance, but is it possible for an application to directly use/output to the DMA buffer allocated by the kernel in hw_params?
Set one of the SND_PCM_ACCESS_MMAP_* access types and then use snd_pcm_mmap_begin/commit.
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.
Thanks a lot.
Pavel.
participants (2)
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Clemens Ladisch -
Pavel Hofman