Subject: Re: [linux-audio-dev] Exact description of PCM system for ALSA
From: Paul Davis (pbd_AT_op.net)
Date: Mon Jul 15 2002 - 20:29:38 EEST
>as i said above, nice work, and nice that someone does this.
>i tried yesterday your mmap implemantation and at least get it to work
>somehow, but im right that:
>
>outbuffer = (area->addr + (area->first + area->step * (offset)) / 8);
>
>returns only a pointer to the buffer? i have to do:
>
> memset(outbuffer, 0, frames_transmit);
> memcpy(outbuffer, data, frames_transmit);
>
>to really wright data to the buffer. i get also some kind of fragments
>staying in buffer if i guess one 'frames_transmit' is smaller than the
>written before or/and if its not aligned to fragment_size, a funny
>effect, but im currently don't know how to clean it up.
forget all this and use snd_pcm_mmap_copy_areas.
forget all that and use ... well, you know ;)
--p
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