[alsa-devel] POSIX clocks and ALSA
Heikki Lindholm
holindho at cs.helsinki.fi
Mon Nov 26 17:04:56 CET 2007
Jaroslav Kysela kirjoitti:
> On Mon, 26 Nov 2007, Heikki Lindholm wrote:
>
>> I had a look at the proposal and the thread at
>> http://thread.gmane.org/gmane.linux.alsa.devel/45237/focus=45573
>
> My initial implementation following proposal is bellow for review and
> comments. I also changed timestamps for ALSA timers to use monotonic
> clocks (can be switched back using a module parameter).
>
> Jaroslav
>
> diff -r 5e8cab953031 core/pcm_lib.c
> --- a/core/pcm_lib.c Mon Nov 26 09:00:56 2007 +0100
<...>
> diff -r 5e8cab953031 include/asound.h
> --- a/include/asound.h Mon Nov 26 09:00:56 2007 +0100
> +++ b/include/asound.h Mon Nov 26 15:02:57 2007 +0100
> @@ -435,6 +435,13 @@ struct snd_xfern {
> };
>
> enum {
> + SNDRV_PCM_TSTAMP_TYPE_GETTIMEOFDAY = 0, /* gettimeofday equivalent */
> + SNDRV_PCM_TSTAMP_TYPE_GETTIMEOFDAY1, /* for compatibility, equal to zero */
> + SNDRV_PCM_TSTAMP_TYPE_MONOTONIC, /* posix_clock_monotonic equivalent */
> + SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC,
> +};
Looks good otherwise, but I'd still like to argue about this
compatibility point: compatibility with what exactly? When was
PCM_TSTAMP ioctl deprecated? Before 1.0.0? Has anyone *ever* used it?
And so, is there any point in adding something not-so-pretty to a new
feature right from the start. Just declare legacy TSTAMP ioctl users
scr*wed! :)
The good thing is that this change has, AFAICS, nothing contradicting
with redesigning the timestamp API, so that could be left open and this
stuff still applied.
-- Heikki Lindholm
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