[asterisk-dev] [RFC] Modularising echo cancellers

[Tzafrir Cohen]

On Thu, Jun 29, 2006 at 10:16:31AM +1200, Nic Bellamy wrote:
> Tzafrir Cohen wrote:
> 
> >On Wed, Jun 28, 2006 at 03:40:02PM +1200, Nic Bellamy wrote:
> > 
> >
> >>Hi all,
> >>  I've developed a patch to Zaptel that modularises the software echo 
> >>cancelers, allowing multiple ones to be loaded simultaneously.
> >>   
> >>
> [snip]
> 
> >>The userspace-kernelspace interface required changes to allow sending a 
> >>canceler name, rather than just on/off requests, so I added a new IOCTL 
> >>interface:
> >>
> >>#define ZT_ECHO_CAN_NAMELEN     (16)
> >>typedef struct zt_echocancelv2
> >>   
> >>
> >
> >Hmmm... I don't like the name. "v2" for version that will actually be
> >used, and the shorter name for the version not to use.
> >
> >And then again, the echo canceller is an implementation detail. Not a
> >matter of interface. Ideally I would like to be able to switch with ECs
> >through /sys/modules/zaptel/parameters or whatever. Please use sysfs or
> >procfs for such implementation details.
> >
> >Thus you could set them at run-time by a script.
> >
> >The fact that you need to switch an echo canceller indicates that the
> >current echo canceller is simply not good enough. But there should be no
> >real need for Asterisk to set the implementation . For the sysadmin:
> >probably yes.
> > 
> >
> The main point about setting them from Asterisk was the ability to set 
> them per-channel for experimentation purposes. I guess it could be done 
> via procfs/sysfs, but that's going to add quite a bit more complexity 
> compared to the ioctl - the ioctl was already there, all I've done is 
> expand its capabilities (and yeah, I know many people hate ioctls...).

# ls -l /sys/class/zaptel/zap1
-r--r--r--  1 root root 4096 2006-06-29 01:39 dev

Zaptel channels are already represented in sysfs. Spans are not
represented there. (If you want to hook to a span, consider adding a write
option to the procfs file of the span).

So what would it take to add there an entry thhat sets the the EC for
that channel?

-- 
Tzafrir Cohen      sip:tzafrir at local.xorcom.com
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