Re: [alsa-devel] [alsa-cvslog] alsa-lib: SND_PCM_TSTAMP_MMAP -> SND_PCM_TSTAMP_ENABLE change
Jaroslav Kysela wrote:
description: SND_PCM_TSTAMP_MMAP -> SND_PCM_TSTAMP_ENABLE change
diff -r 3c87e22e70d8 -r 2519fcd54901 include/pcm.h --- a/include/pcm.h Thu Jan 10 10:01:14 2008 +0100 +++ b/include/pcm.h Fri Jan 11 08:54:07 2008 +0100 @@ -281,9 +281,9 @@ typedef enum _snd_pcm_tstamp { /** No timestamp */ SND_PCM_TSTAMP_NONE = 0,
- /** Update mmap'ed timestamp */
- SND_PCM_TSTAMP_MMAP,
- SND_PCM_TSTAMP_LAST = SND_PCM_TSTAMP_MMAP
- /** Update timestamp at every hardware position update */
- SND_PCM_TSTAMP_ENABLE,
- SND_PCM_TSTAMP_LAST = SND_PCM_TSTAMP_ENABLE
} snd_pcm_tstamp_t;
This change breaks backward compatibility. The v19-devel branch of PortAudio uses SND_PCM_TSTAMP_MMAP.
Regards, Clemens
On Fri, 11 Jan 2008, Clemens Ladisch wrote:
Jaroslav Kysela wrote:
description: SND_PCM_TSTAMP_MMAP -> SND_PCM_TSTAMP_ENABLE change
diff -r 3c87e22e70d8 -r 2519fcd54901 include/pcm.h --- a/include/pcm.h Thu Jan 10 10:01:14 2008 +0100 +++ b/include/pcm.h Fri Jan 11 08:54:07 2008 +0100 @@ -281,9 +281,9 @@ typedef enum _snd_pcm_tstamp { /** No timestamp */ SND_PCM_TSTAMP_NONE = 0,
- /** Update mmap'ed timestamp */
- SND_PCM_TSTAMP_MMAP,
- SND_PCM_TSTAMP_LAST = SND_PCM_TSTAMP_MMAP
- /** Update timestamp at every hardware position update */
- SND_PCM_TSTAMP_ENABLE,
- SND_PCM_TSTAMP_LAST = SND_PCM_TSTAMP_ENABLE
} snd_pcm_tstamp_t;
This change breaks backward compatibility. The v19-devel branch of PortAudio uses SND_PCM_TSTAMP_MMAP.
It's no problem to add SND_PCM_TSTAMP_MMAP as alias to SND_PCM_TSTAMP_ENABLE back. But I think that it would be better to let developers using SND_PCM_TSTAMP_MMAP realize that something was changed.
Binary compatibility is kept.
Note that SND_PCM_TSTAMP_MMAP is also quite unusable without new snd_pcm_htimestamp() function and support for monotonic timestamps in the latest driver/library code.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.
At Fri, 11 Jan 2008 09:35:08 +0100 (CET), Jaroslav Kysela wrote:
On Fri, 11 Jan 2008, Clemens Ladisch wrote:
Jaroslav Kysela wrote:
description: SND_PCM_TSTAMP_MMAP -> SND_PCM_TSTAMP_ENABLE change
diff -r 3c87e22e70d8 -r 2519fcd54901 include/pcm.h --- a/include/pcm.h Thu Jan 10 10:01:14 2008 +0100 +++ b/include/pcm.h Fri Jan 11 08:54:07 2008 +0100 @@ -281,9 +281,9 @@ typedef enum _snd_pcm_tstamp { /** No timestamp */ SND_PCM_TSTAMP_NONE = 0,
- /** Update mmap'ed timestamp */
- SND_PCM_TSTAMP_MMAP,
- SND_PCM_TSTAMP_LAST = SND_PCM_TSTAMP_MMAP
- /** Update timestamp at every hardware position update */
- SND_PCM_TSTAMP_ENABLE,
- SND_PCM_TSTAMP_LAST = SND_PCM_TSTAMP_ENABLE
} snd_pcm_tstamp_t;
This change breaks backward compatibility. The v19-devel branch of PortAudio uses SND_PCM_TSTAMP_MMAP.
It's no problem to add SND_PCM_TSTAMP_MMAP as alias to SND_PCM_TSTAMP_ENABLE back. But I think that it would be better to let developers using SND_PCM_TSTAMP_MMAP realize that something was changed.
I think we shouldn't break the API, at least. Let's add alias.
Binary compatibility is kept.
Note that SND_PCM_TSTAMP_MMAP is also quite unusable without new snd_pcm_htimestamp() function and support for monotonic timestamps in the latest driver/library code.
Right. It's meaningless without the fast timestamp read. The result is as same as TSTAMP_NONE. Maybe they took it blindly (because of the name 'TSTAMP_NONE').
Regarding this change, one idea that came to my mind is to rename this API function. For example, snd_pcm_sw_params_get/set_fast_tstamp(sw, bool), and deprecate snd_pcm_sw_params_get/set_tstamp_mode(). The bool function seems more intuitive in this case. The mode enum might be good if we'll have more complicated timestamp modes, but I don't think this will ever happen...
Takashi
participants (3)
-
Clemens Ladisch -
Jaroslav Kysela -
Takashi Iwai