[pulseaudio-discuss] [PATCH]raop2: Blocking UDP sockets

[Hajime Fujita]

Hi Matthias,

Thank you for the patch.

I modified the code and commit message a bit and included in my tree.
https://github.com/hfujita/pulseaudio-raop2/commit/1d77def11875dc78454a00927c735a4589e67944


Thanks,
Hajime

Matthias Wabersich wrote:
> Hi Rémi, hi Hajime,
> 
>>>> 1) it would consume  100% of the CPU time
>>> No, it won't. poll() will *not* return immediately.
>>
>> Oh you're right. For some reason I misunderstood that poll(..., -1)
>> meant "no wait, return immediately" but actually it was "no timeout,
>> wait forever".
>>...
>>>> 2) it would block the  message loop (I'm not sure about the real
>>>> implication of this, though)
>>>
>>> But yes.
> 
> I understand that either way poll() would block the message loop.
> I re-wrote my patch so that packets are discarded when blocking occurs
> (as was my first thought, and Hajime's suggestion as well).
> You can find it in my fork of Hajime's repository on github [1] and
> attached below.
> 
> Greetings,
> 
> Matthias
> 
> [1]:
> https://github.com/emwe/pulseaudio-raop2/commit/d9b9c822ef1d0b2b55601b0d2958190644e574fc
> 
> 
> diff --git a/src/modules/raop/raop_client.c
> b/src/modules/raop/raop_client.c
> index f699fd8..eb4a582 100644
> --- a/src/modules/raop/raop_client.c
> +++ b/src/modules/raop/raop_client.c
> @@ -560,7 +560,10 @@ static ssize_t udp_send_audio_packet(pa_raop_client
> *c, bool retrans, uint8_t *b
>      int fd = retrans ? c->udp_control_fd : c->udp_stream_fd;
> 
>      length = pa_write(fd, buffer, size, NULL);
> -
> +    if ((length == -1) && ((errno == EAGAIN) || (errno == EWOULDBLOCK))) {
> +        pa_log_debug("Discarding audio packet %d (blocking)", c->seq);
> +        length = size;
> +    }
>      return length;
>  }
> 
>