[alsa-devel] snd_pcm_ops - .copy

Takashi Iwai tiwai at suse.de
Mon Apr 21 18:00:27 CEST 2008

At Mon, 21 Apr 2008 19:27:45 +0530,
Harsha priya gupta wrote:
> Hi,
> I am trying to implement the .copy function of playack_ops in my driver. But
> when I try playing an mp3 file, my .copy's function code path was executing.
> Suddenly I do not see that function being called. Can anyone help me
> understand when the following code path will be executed
> snd_pcm_lib_write_transfer
>    substream->ops->copy

Do you use a mmap method?  If so, the copy callback won't be called.
The copy callback is only for copying the data from the user-space
buffer to the driver buffer, which is skipped via mmap.


More information about the Alsa-devel mailing list