[lkml]   [2006]   [Jan]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [Alsa-devel] Re: [OT] ALSA userspace API complexity
On Mon, Jan 09, 2006 at 04:29:45PM -0800, David Lang wrote:
> On Tue, 10 Jan 2006, John Rigg wrote:
> >>does the CPU touch the data for these, or do you DMA directly from
> >>userspace (i.e. "zero-copy")?
> >
> >The cards I mentioned use DMA. RME actually advertises that some of their
> >cards can handle 52 channels with zero CPU load. Their onboard DSPs can
> >also do routing and mixing, again without touching the CPU.
> I was under the (apparently mistaken) impression that you couldn't DMA
> from userspace (something to do with the possibility that the userspace
> memory pages could be swapped out in the middle of the DMA)

Hmm. Maybe I've been paying too much attention to card vendors'
sales talk :)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2006-01-10 02:19    [W:0.223 / U:0.496 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site