pcm: hw: add a helper function just to query status data

When mapping status data successfully, mapped page includes status data
for applications. In this case, applications have no need to call ioctl(2)
with SNDRV_PCM_IOCTL_SYNC_PTR. However, in current implementation, when
map of control data is unavailable, applications execute the ioctl(2).
This is inconvenient for some cases that applications require to query
status only.

This commit adds a helper function to query status data without issuing
the control in fallback mode from failure of status mmap.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c
index 9963523ccb4fad5c0187bd45e12f1dc5e02e56c6..38d975afef0aa3a31f8756789a044a4c06d13d28 100644 (file)
--- a/src/pcm/pcm_hw.c
+++ b/src/pcm/pcm_hw.c
@@ -165,6 +165,20 @@ static int query_status_and_control_data(snd_pcm_hw_t *hw)
                         SNDRV_PCM_SYNC_PTR_AVAIL_MIN);
 }
 
+static int query_status_data(snd_pcm_hw_t *hw)
+{
+       if (!hw->mmap_status_fallbacked)
+               return 0;
+
+       /*
+        * Query both of control/status data to avoid unexpected change of
+        * control data in kernel space.
+        */
+       return sync_ptr1(hw,
+                        SNDRV_PCM_SYNC_PTR_APPL |
+                        SNDRV_PCM_SYNC_PTR_AVAIL_MIN);
+}
+
 static int snd_pcm_hw_clear_timer_queue(snd_pcm_hw_t *hw)
 {
        if (hw->period_timer_need_poll) {
@@ -349,7 +363,7 @@ static int snd_pcm_hw_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params)
        params->info &= ~0xf0000000;
        if (pcm->tstamp_type != SND_PCM_TSTAMP_TYPE_GETTIMEOFDAY)
                params->info |= SND_PCM_INFO_MONOTONIC;
-       return sync_ptr(hw, 0);
+       return query_status_data(hw);
 }
 
 static void snd_pcm_hw_close_timer(snd_pcm_hw_t *hw)
@@ -556,7 +570,7 @@ static int snd_pcm_hw_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
 static snd_pcm_state_t snd_pcm_hw_state(snd_pcm_t *pcm)
 {
        snd_pcm_hw_t *hw = pcm->private_data;
-       int err = sync_ptr(hw, 0);
+       int err = query_status_data(hw);
        if (err < 0)
                return err;
        return (snd_pcm_state_t) hw->mmap_status->state;
@@ -1064,7 +1078,7 @@ static snd_pcm_sframes_t snd_pcm_hw_avail_update(snd_pcm_t *pcm)
        snd_pcm_hw_t *hw = pcm->private_data;
        snd_pcm_uframes_t avail;
 
-       sync_ptr(hw, 0);
+       query_status_data(hw);
        avail = snd_pcm_mmap_avail(pcm);
        switch (FAST_PCM_STATE(hw)) {
        case SNDRV_PCM_STATE_RUNNING: