[USRP-users] B210 Second CODEC Loopback Fail - SOLUTION

Dario Fertonani dario.fertonani at gmail.com
Thu Oct 1 12:15:23 EDT 2015


It works here! Thank you.
Haswell CPU and Broadwell CPU both seem to need just one additional call to
peek64.

On Thu, Oct 1, 2015 at 8:52 AM, Tom Wallace via USRP-users <
usrp-users at lists.ettus.com> wrote:

> If anyone else is seeing the B210 second CODEC loopback test fail
> intermittently with UHD 3.9.x, as I was, the following change kills the
> problem for me:
>
>
>
> diff --git a/host/lib/usrp/common/ad936x_manager.cpp
> b/host/lib/usrp/common/ad936x_manager.cpp
>
> index 8c88978..60a09d3 100644
>
> --- a/host/lib/usrp/common/ad936x_manager.cpp
>
> +++ b/host/lib/usrp/common/ad936x_manager.cpp
>
> @@ -94,7 +94,8 @@ class ad936x_manager_impl : public ad936x_manager
>
>              boost::hash_combine(hash, i);
>
>              const boost::uint32_t word32 = boost::uint32_t(hash) &
> 0xfff0fff0;
>
>              iface->poke32(codec_idle_addr, word32);
>
> -            // We do 2 peeks so we have enough idleness for loopback to
> propagate
>
> +            // We do 3 peeks so we have enough idleness for loopback to
> propagate
>
> +            iface->peek64(codec_readback_addr);
>
>              iface->peek64(codec_readback_addr);
>
>              const boost::uint64_t rb_word64 =
> iface->peek64(codec_readback_addr);
>
>              const boost::uint32_t rb_tx = boost::uint32_t(rb_word64 >>
> 32);
>
>
>
> This is probably the wrong way to fix it, of course – it could just fail
> again on a faster machine, unless there’s some definite relationship
> between the time it takes a peek to complete and the amount of delay
> required. I’ll leave the appropriate permanent fix to the Ettus guys.
>
>
>
> Thanks to Ian Buckley for help in tracking this down.
>
>
>
> ---
>
>   Tom Wallace (tom.wallace at vesperix.com)
>
>   Vesperix Corporation
>
>   803 West Broad Street, Suite 520
>
>   Falls Church, VA 22046
>
>   Phone 703-224-4422   Mobile 703-220-8711
>
>
>
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
>
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