uaudio patch, configurable buffer size

[Pyun YongHyeon]

On Sun, Mar 06, 2005 at 10:28:23PM -0500, Mathew Kanner wrote:
[...]
 > 	Per your other e-mail, as present in the source, is having the
 > default size of 16*1024 and doing bus_dma_tag_create with a maxsegz of
 > 0x3fff (16*1024-1) a bug?

I think so. I couldn't verify it since I don't have real
hardware and don't know USB audio internals. But I believe
almost all audio hardwares can transfer upto 64KB in a single
DMA request.
Many device drivers for PCI audio cards use 0x3ffff(256KB - 1).
I don't know those hardwares can transfer upto that huge size
and hardly believe this. But pcm(4) further restricts the buffer
size to 64KB in pcm_getbuffersize and we created DMA tag with
single segment, so it would be OK to use 0x3ffff.

-- 
Regards,
Pyun YongHyeon
http://www.kr.freebsd.org/~yongari	|	yongari at freebsd.org