Re: [Discuss-gnuradio] proposed change to ugen to enable USRP to work well on NetBSD

[LRK]

On Wed, May 03, 2006 at 02:00:23PM -0400, Greg Troxel wrote:
>
> At BBN we are working on a project involving teams of
> cognitively-controlled software radios, funded by the US government.
> As part of this, we will be using GNU Radio on NetBSD.  Due to the
> current implementation of ugen(4) (generic USB devices), reads from
> the USRP are not pipelined and transfer rates top out at around 4
> MB/s.
> 
> Joanne has written a proposal to modify NetBSD's ugen(4) to get good
> performance for the USRP.  We'd like feedback about the technical
> approach.  (Once we have it working, the changes will be commited to
> NetBSD-current.)

I would like to run GR under FreeBSD so I am looking forward to your
progress on this.


Under FreeBSD (and probably NetBSD) the ugen(4) device is generic and gets
assigned to any unknown device. I would suggest you look into getting a
number assigned to the USRP and a name assigned for it, say usrp(4). Any
application more serious than experimental would seem to justify it.


The ehci(4) driver is for USB 2.0 and the FreeBSD version contains
comments which indicate it may be the problem. I don't quite understand
all the intracacies here but the code seems much too complicated for the
job. Ah for the good ol' days when I/O was less than a hundred lines of
assembler code and two buffers were enough. :)



-- 
LRK
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