ALSA: pcm: Introduce protocol version field to sw_params

For controlling the new fields more strictly, add sw_params.proto
field indicating the protocol version of the user-space.  User-space
should fill the SNDRV_PCM_VERSION value it's built with, then kernel
can know whether the new fields should be evaluated or not.

And now tstamp_type field is evaluated only when the valid value is
set there.  This avoids the wrong override of tstamp_type to zero,
which is SNDRV_PCM_TSTAMP_TYPE_GETTIMEOFDAY.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 4 insertions, 2 deletions

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 81dedc381efd..8cd2f930ad0b 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -543,7 +543,8 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
 
         if (params->tstamp_mode > SNDRV_PCM_TSTAMP_LAST)
                 return -EINVAL;
-        if (params->tstamp_type > SNDRV_PCM_TSTAMP_TYPE_LAST)
+        if (params->proto >= SNDRV_PROTOCOL_VERSION(2, 0, 12) &&
+            params->tstamp_type > SNDRV_PCM_TSTAMP_TYPE_LAST)
                 return -EINVAL;
         if (params->avail_min == 0)
                 return -EINVAL;
@@ -559,7 +560,8 @@ static int snd_pcm_sw_params(struct snd_pcm_substream *substream,
         err = 0;
         snd_pcm_stream_lock_irq(substream);
         runtime->tstamp_mode = params->tstamp_mode;
-        runtime->tstamp_type = params->tstamp_type;
+        if (params->proto >= SNDRV_PROTOCOL_VERSION(2, 0, 12))
+                runtime->tstamp_type = params->tstamp_type;
         runtime->period_step = params->period_step;
         runtime->control->avail_min = params->avail_min;
         runtime->start_threshold = params->start_threshold;