lib.sh: switch to use cavstool to dump the etrace

we will use the Zephyr logging tool to dump the etrace
form the shared memory for all Zephyr platforms.

Signed-off-by: Keqiao Zhang <keqiao.zhang@intel.com>

Author: keqiaozhang

case-lib/lib.sh

@@ -352,7 +352,17 @@ func_lib_start_log_collect()
 
     if [ "X$is_etrace" == "X0" ];then
         logfile=$LOG_ROOT/slogger.txt
+
+        # start cavstool in the background to collect the etrace.
+        # Since cavstool can follow a ring buffer in etrace, so it should be
+        # started at the start of the test and we would not miss any Zephyr logs.
+        is_zephyr && func_cavstool_etrace_collect
     else
+        # cavstool starts at the beginning of the test, we don't need to start
+        # it again. We only need to start sof-logger to collect the etrace logs
+        # only for the non-zephyr platforms at the end of a test.
+        is_zephyr && return 0
+
         logfile=$LOG_ROOT/etrace.txt
         logopt=""
     fi