tinyalsa: pcm: open pcm driver in non blocking modeandroid-cts_7.1_r1android-cts-7.1_r9android-cts-7.1_r8android-cts-7.1_r7android-cts-7.1_r6android-cts-7.1_r5android-cts-7.1_r4android-cts-7.1_r3android-cts-7.1_r29android-cts-7.1_r28android-cts-7.1_r27android-cts-7.1_r26android-cts-7.1_r25android-cts-7.1_r24android-cts-7.1_r23android-cts-7.1_r22android-cts-7.1_r21android-cts-7.1_r20android-cts-7.1_r2android-cts-7.1_r19android-cts-7.1_r18android-cts-7.1_r17android-cts-7.1_r16android-cts-7.1_r15android-cts-7.1_r14android-cts-7.1_r13android-cts-7.1_r12android-cts-7.1_r11android-cts-7.1_r10android-cts-7.1_r1android-7.1.1_r9android-7.1.1_r8android-7.1.1_r7android-7.1.1_r61android-7.1.1_r60android-7.1.1_r6android-7.1.1_r59android-7.1.1_r58android-7.1.1_r57android-7.1.1_r56android-7.1.1_r55android-7.1.1_r54android-7.1.1_r53android-7.1.1_r52android-7.1.1_r51android-7.1.1_r50android-7.1.1_r49android-7.1.1_r48android-7.1.1_r47android-7.1.1_r46android-7.1.1_r45android-7.1.1_r44android-7.1.1_r43android-7.1.1_r42android-7.1.1_r41android-7.1.1_r40android-7.1.1_r4android-7.1.1_r39android-7.1.1_r38android-7.1.1_r35android-7.1.1_r33android-7.1.1_r32android-7.1.1_r31android-7.1.1_r3android-7.1.1_r28android-7.1.1_r27android-7.1.1_r26android-7.1.1_r25android-7.1.1_r24android-7.1.1_r23android-7.1.1_r22android-7.1.1_r21android-7.1.1_r20android-7.1.1_r2android-7.1.1_r17android-7.1.1_r16android-7.1.1_r15android-7.1.1_r14android-7.1.1_r13android-7.1.1_r12android-7.1.1_r11android-7.1.1_r10android-7.1.1_r1android-7.1.0_r7android-7.1.0_r6android-7.1.0_r5android-7.1.0_r4android-7.1.0_r3android-7.1.0_r2android-7.1.0_r1nougat-mr1.8-releasenougat-mr1.7-releasenougat-mr1.6-releasenougat-mr1.5-releasenougat-mr1.4-releasenougat-mr1.3-releasenougat-mr1.2-releasenougat-mr1.1-releasenougat-mr1-volantis-releasenougat-mr1-security-releasenougat-mr1-releasenougat-mr1-flounder-releasenougat-mr1-devnougat-mr1-cts-releasenougat-dr1-release

- in current implementation pcm open call is blocking hence if pcm_open
  is done on same driver twice second pcm open will get blocked till
  first instance of the PCM driver is not released.
  In times this will result in deadlock.

- fix this issue by making PCM open in non-blocking mode.

- after pcm open is successful, in non-blocking mode, change the device
  mode to blocking again to make sure rest of the operation on the
  driver, like read / write calls, are always called in blocking mode.

Also fix jump to wrong label in case of failure before mmap().

Bug: 29865791
Bug: 30388410
Change-Id: I95c0ad8456e6c2bb3bfb48813e1db75cdef387f8

1 files changed, 8 insertions, 2 deletions

diff --git a/pcm.c b/pcm.c
index 394faba..78e1cea 100644
--- a/pcm.c
+++ b/pcm.c
@@ -855,12 +855,18 @@ struct pcm *pcm_open(unsigned int card, unsigned int device,
              flags & PCM_IN ? 'c' : 'p');
 
     pcm->flags = flags;
-    pcm->fd = open(fn, O_RDWR);
+    pcm->fd = open(fn, O_RDWR|O_NONBLOCK);
     if (pcm->fd < 0) {
         oops(pcm, errno, "cannot open device '%s'", fn);
         return pcm;
     }
 
+    if (fcntl(pcm->fd, F_SETFL, fcntl(pcm->fd, F_GETFL) &
+              ~O_NONBLOCK) < 0) {
+        oops(pcm, errno, "failed to reset blocking mode '%s'", fn);
+        goto fail_close;
+    }
+
     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_INFO, &info)) {
         oops(pcm, errno, "cannot get info");
         goto fail_close;
@@ -884,7 +890,7 @@ struct pcm *pcm_open(unsigned int card, unsigned int device,
     if (flags & PCM_NOIRQ) {
         if (!(flags & PCM_MMAP)) {
             oops(pcm, -EINVAL, "noirq only currently supported with mmap().");
-            goto fail;
+            goto fail_close;
         }
 
         params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;