Improved mmap emulation over write/read

diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c
index 522e55a73e63499d2bf5c009702f895a1d1836c6..928f4efe5eca72b28d405c90669dca3b1c816507 100644 (file)
--- a/src/pcm/pcm_hw.c
+++ b/src/pcm/pcm_hw.c
@@ -45,12 +45,19 @@ typedef struct {
        int card, device, subdevice;
        volatile struct sndrv_pcm_mmap_status *mmap_status;
        struct sndrv_pcm_mmap_control *mmap_control;
+       int shadow_appl_ptr: 1, avail_update_flag: 1;
+       snd_pcm_uframes_t appl_ptr;
        int shmid;
 } snd_pcm_hw_t;
 
 #define SNDRV_FILE_PCM_STREAM_PLAYBACK         "/dev/snd/pcmC%iD%ip"
 #define SNDRV_FILE_PCM_STREAM_CAPTURE          "/dev/snd/pcmC%iD%ic"
-#define SNDRV_PCM_VERSION_MAX  SNDRV_PROTOCOL_VERSION(2, 0, 0)
+#define SNDRV_PCM_VERSION_MAX                  SNDRV_PROTOCOL_VERSION(2, 0, 0)
+
+/* update appl_ptr with driver */
+#define UPDATE_SHADOW_PTR(hw) \
+       do { if (hw->shadow_appl_ptr && !hw->avail_update_flag) \
+              hw->appl_ptr = hw->mmap_control->appl_ptr; } while (0)
 
 static int snd_pcm_hw_nonblock(snd_pcm_t *pcm, int nonblock)
 {
@@ -134,6 +141,16 @@ static int snd_pcm_hw_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params)
                SYSERR("SNDRV_PCM_IOCTL_HW_PARAMS failed");
                return -errno;
        }
+       if (pcm->stream == SND_PCM_STREAM_CAPTURE) {
+               if (!(params->info & SNDRV_PCM_INFO_MMAP)) {
+                       hw->shadow_appl_ptr = 1;
+                       hw->appl_ptr = 0;
+                       pcm->appl_ptr = &hw->appl_ptr;
+               } else {
+                       hw->shadow_appl_ptr = 0;
+                       pcm->appl_ptr = &hw->mmap_control->appl_ptr;
+               }
+       }
        return 0;
 }
 
@@ -358,6 +375,7 @@ static snd_pcm_sframes_t snd_pcm_hw_readi(snd_pcm_t *pcm, void *buffer, snd_pcm_
        result = ioctl(fd, SNDRV_PCM_IOCTL_READI_FRAMES, &xferi);
        if (result < 0)
                return -errno;
+       UPDATE_SHADOW_PTR(hw);
        return xferi.result;
 }
 
@@ -372,6 +390,7 @@ static snd_pcm_sframes_t snd_pcm_hw_readn(snd_pcm_t *pcm, void **bufs, snd_pcm_u
        result = ioctl(fd, SNDRV_PCM_IOCTL_READN_FRAMES, &xfern);
        if (result < 0)
                return -errno;
+       UPDATE_SHADOW_PTR(hw);
        return xfern.result;
 }
 
@@ -467,28 +486,42 @@ static int snd_pcm_hw_close(snd_pcm_t *pcm)
        return 0;
 }
 
-static snd_pcm_sframes_t snd_pcm_hw_mmap_commit(snd_pcm_t *pcm,
-                                               snd_pcm_uframes_t offset ATTRIBUTE_UNUSED,
-                                               snd_pcm_uframes_t size)
+static int snd_pcm_hw_mmap_commit(snd_pcm_t *pcm,
+                                 snd_pcm_uframes_t offset ATTRIBUTE_UNUSED,
+                                 snd_pcm_uframes_t size)
 {
-       if (!(pcm->info & SND_PCM_INFO_MMAP) && 
-           pcm->stream == SND_PCM_STREAM_PLAYBACK)
-               return snd_pcm_write_mmap(pcm, size);
+       if (!(pcm->info & SND_PCM_INFO_MMAP)) {
+               if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
+                       snd_pcm_sframes_t res;
+                       do {
+                               res = snd_pcm_write_mmap(pcm, size);
+                               if (res < 0)
+                                       return res;
+                               size -= res;
+                       } while (size > 0);
+                       return 0;
+               } else {
+                       snd_pcm_hw_t *hw = pcm->private_data;
+                       assert(hw->shadow_appl_ptr);
+               }
+       }
        snd_pcm_mmap_appl_forward(pcm, size);
-       return size;
+       return 0;
 }
 
 static snd_pcm_sframes_t snd_pcm_hw_avail_update(snd_pcm_t *pcm)
 {
        snd_pcm_uframes_t avail;
-       snd_pcm_sframes_t err;
        if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
                avail = snd_pcm_mmap_playback_avail(pcm);
        } else {
                avail = snd_pcm_mmap_capture_avail(pcm);
-               if (avail > 0 && 
-                   !(pcm->info & SND_PCM_INFO_MMAP)) {
+               if (avail > 0 && !(pcm->info & SND_PCM_INFO_MMAP)) {
+                       snd_pcm_sframes_t err;
+                       snd_pcm_hw_t *hw = pcm->private_data;
+                       hw->avail_update_flag = 1;
                        err = snd_pcm_read_mmap(pcm, avail);
+                       hw->avail_update_flag = 0;
                        if (err < 0)
                                return err;
                        assert((snd_pcm_uframes_t)err == avail);