Re: [patch 1/1] pc-speaker: add SND_SILENT

[Vojtech Pavlik <vojtech@suse.cz>]

On Fri, Mar 31, 2006 at 11:06:35PM +0200, Edgar Toernig wrote:
> Vojtech Pavlik wrote:
> >
> > On Fri, Mar 31, 2006 at 01:07:34AM +0200, Edgar Toernig wrote:
> > >
> > > Latency is no problem.  I'm using a userspace daemon to emulate
> > > the console beeper for about 6 months now and it work's very well.
> > > 
> > > The daemon listens on /dev/input/eventX and when receiving a
> > 
> > It needs to use /dev/input/uinput, not eventX. SND_TONE events are not
> > sent to the event devices.
> 
> Well, I get them - stock 2.6.16.

Oh, yes, you're right. But still, this will only work if a speaker
device is present, so uinput is the right way to do it.

> > > Latency isn't noticable and memory footprint is small.
> > 
> > It needs to have the sample ready in memory and not swapped out. Then
> > the latency will be OK, but if it needs to read it in from the disk, it
> > may be very noticeable.
> 
> Yeah, if one ever cares one could mlock the samples, or (as I do) run
> without swap.  Fixing the 'air' latency of 3ms/m is harder though *g*

-- 
Vojtech Pavlik
Director SuSE Labs