From 1d40dd7e32b3c97e85b5bf9bd436540ae4f98fb5 Mon Sep 17 00:00:00 2001
From: Sharvil Nanavati <sharvil@google.com>
Date: Tue, 28 Oct 2014 23:43:59 -0700
Subject: [PATCH] A2DP sink: reply with success on Start command.

We've observed a Nexus 5 sending back-to-back START requests. If we
accept the first request and move to the STREAMING state, we'll reject
subsequent requests. The phone, however, ignores the first response
(since it has already issued another START) and will not route audio
to Glass.

This is a speculative fix. If we're in the STREAMING state and we
get an incoming START request, accept the request instead of rejecting
it to work around a buggy implementation on the peer.

Bug: 18165461
---
 stack/avdt/avdt_scb.c | 40 +++++++++++++++++-----------------------
 1 file changed, 17 insertions(+), 23 deletions(-)

diff --git a/stack/avdt/avdt_scb.c b/stack/avdt/avdt_scb.c
index 0b6885953..2e653bd61 100644
--- a/stack/avdt/avdt_scb.c
+++ b/stack/avdt/avdt_scb.c
@@ -730,41 +730,36 @@ UINT8 avdt_scb_verify(tAVDT_CCB *p_ccb, UINT8 state, UINT8 *p_seid, UINT16 num_s
     int         i;
     tAVDT_SCB   *p_scb;
     UINT8       nsc_mask;
-    UINT8       chk_state;
     UINT8       ret = 0;
 
     AVDT_TRACE_DEBUG("avdt_scb_verify state %d", state);
     /* set nonsupported command mask */
     /* translate public state into private state */
     nsc_mask = 0;
-    chk_state = AVDT_SCB_STREAM_ST;
-    switch(state)
-    {
-    case AVDT_VERIFY_SUSPEND:
-        nsc_mask = AVDT_NSC_SUSPEND;
-        break;
-    case AVDT_VERIFY_OPEN:
-    case AVDT_VERIFY_START:
-        chk_state = AVDT_SCB_OPEN_ST;
-        break;
-    }
+    if (state == AVDT_VERIFY_SUSPEND)
+      nsc_mask = AVDT_NSC_SUSPEND;
 
     /* verify every scb */
-    for (i = 0; i < num_seid; i++)
+    for (i = 0, *p_err_code = 0; i < num_seid && *p_err_code == 0; i++)
     {
         if ((p_scb = avdt_scb_by_hdl(p_seid[i])) == NULL)
-        {
             *p_err_code = AVDT_ERR_BAD_STATE;
-            break;
-        }
-        else if ((p_scb->state != chk_state) || (p_scb->p_ccb != p_ccb))
-        {
+        else if (p_scb->p_ccb != p_ccb)
             *p_err_code = AVDT_ERR_BAD_STATE;
-            break;
-        }
         else if (p_scb->cs.nsc_mask & nsc_mask)
-        {
             *p_err_code = AVDT_ERR_NSC;
+
+        switch (state) {
+          case AVDT_VERIFY_OPEN:
+          case AVDT_VERIFY_START:
+            if (p_scb->state != AVDT_SCB_OPEN_ST && p_scb->state != AVDT_SCB_STREAM_ST)
+              *p_err_code = AVDT_ERR_BAD_STATE;
+            break;
+
+          case AVDT_VERIFY_SUSPEND:
+          case AVDT_VERIFY_STREAMING:
+            if (p_scb->state != AVDT_SCB_STREAM_ST)
+              *p_err_code = AVDT_ERR_BAD_STATE;
             break;
         }
     }
@@ -773,8 +768,7 @@ UINT8 avdt_scb_verify(tAVDT_CCB *p_ccb, UINT8 state, UINT8 *p_seid, UINT16 num_s
     {
         ret = p_seid[i];
     }
-    AVDT_TRACE_DEBUG("avdt_scb_verify state %d, nsc_mask0x%x, ret: %d",
-        chk_state, nsc_mask, ret);
+
     return ret;
 }
 
-- 
2.11.0