Radivoje Jovanovic wrote: > I am allocating memory for the buffers in my init call by doing: > snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS, > snd_dma_continuous_data(GFP_KERNEL), 256*1024, 256*1024); > > in my hw_params call I have: > ret= snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params)); > > here is the output from my hw_params call: > > called snd_pcm_lib_malloc_pages return=1 > params_buffer_bytes(hw_params)=32768 > Size of DMA area=32768 > Buffer size in bytes=262144 > Buffer virt address=9dc00000 > Buffer phys address=0 > > Now I am not sure why is my buffer size bigger than my DMA area. You did not say which values are output, but 262144 is 256*1024, so this is the preallocated buffer. The DMA is what is actually used with the current hw_params. > I assume that memory is not linear because of that SNDRV_DMA_TYPE_CONTINUOUS gives you continguous pages. > and that is why I do not have phys address to the buffer. It doesn't give you the physical address; it looks as if this memory is intended to be accessed only by the CPU. To get coherent memory with a DMA address for a specific device, use SNDRV_DMA_TYPE_DEV. (This must be supported by your architecture.) Regards, Clemens _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
