[alsa-devel] DMA Physical Addr Issue.

Adish Kuvelker adkuvi at gmail.com
Mon Jul 19 14:05:59 CEST 2010


I have allocated the DMA memory using the function
"snd_pcm_lib_preallocate_pages_for_all" passing SNDRV_DMA_TYPE_DEV and
"card->dev" as inputs to the function. Later, in the hw_params call
out function I allocate pages to the requested DMA memory region using
the function "snd_pcm_lib_malloc_pages".

I play a wav file "Noise.wav" from command line by giving the following command

./aplay --file-type wav -f dat Noise.wav

And, when I print the DMA region physical address in the "prepare"
call out through "dma_addr" member of the runtime structure I get a
weird decimal value of "-1036562432" as the physical address.

Can anyone point where I might be going wrong in the whole DMA memory


More information about the Alsa-devel mailing list