[pulseaudio-discuss] [PATCH] "pipe-sink" added option "use_system_clock_for_timing"

[Tanu Kaskinen]

On Sat, 2017-12-16 at 16:57 +0100, Samo Pogačnik wrote:
> +static ssize_t pipe_sink_write(struct userdata *u, pa_memchunk *pchunk) {
> +    size_t index, length;
> +    ssize_t count = 0;
> +    void *p;
> +
> +    pa_assert(u);
> +    pa_assert(pchunk);
> +
> +    index = pchunk->index;
> +    length = pchunk->length;
> +    p = pa_memblock_acquire(pchunk->memblock);
> +
> +    for (;;) {
> +        ssize_t l;
> +
> +        l = pa_write(u->fd, (uint8_t*) p + index, length, &u->write_type);
> +
> +        pa_assert(l != 0);
> +
> +        if (l < 0) {
> +            if (errno == EAGAIN)
> +                break;
> +            else if (errno != EINTR) {
> +                if (!u->fifo_error) {
> +                    pa_log("Failed to write data to FIFO: %s", pa_cstrerror(errno));
> +                    u->fifo_error = true;
> +                }
> +                count = l - count;

process_render_use_timing() assumes that l is -1, so you should replace
l with -1 here.

> +                break;
> +            }
> +        } else {
> +            count += l;
> +            index += l;
> +            length -= l;
> +
> +            if (length <= 0) {
> +                break;
> +            }
> +        }
> +    }
> +
> +    pa_memblock_release(pchunk->memblock);
> +
> +    if (u->fifo_error && count >= 0) {
> +        pa_log("Recovered from FIFO error");
> +        u->fifo_error = false;
> +    }

This logic is not right. If in the first loop iteration pa_write() does
a partial write and then an error occurs during the second iteration,
the code incorrectly thinks that we have recovered from the error. The
recovery happens when pa_write() returns a positive number for the
first time.

Also, use pa_log_debug() or pa_log_info(). pa_log() is an alias for
pa_log_error(), and this is not an error message.

> +    return count;
> +}
> +
> +static int process_render_use_timing(struct userdata *u, pa_usec_t now) {

The function return type can be changed to void.

-- 
Tanu

https://www.patreon.com/tanuk