case-lib: apause: Make sure the PCM is running before pausing

This change addresses the following error seen when doing pause with the
multiple-pause-resume test:
aplay: do_pause:1586: pause push error: File descriptor in bad state

When an xrun happens during the test, the application tries to recover
from the xrun by preparing and restarting the stream. There could be a
race between when this happens and when the script tries to pause the
stream. To avoid this, make sure that the stream state is RUNNING before
going ahead with the pause.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

Author: ranj063

case-lib/apause.exp

@@ -107,6 +107,29 @@ proc cr_to_lf {arg} {
 #
 #    arecord $cmd_opts -D $dev -r $rate -c $channel -f $fmt -vv -i $file_name ...
 log 0 "$argv0 spawning: $argv"
+
+set device [lindex $argv 2]
+set command [lindex $argv 0]
+
+# Determine direction based on the command
+if {$command eq "aplay"} {
+    set direction "p"  ; # Playback
+} else {
+    set direction "c"  ; # Capture
+}
+
+# parse the card number and device
+if {![regexp {hw:(\d+),(\d+)} $device match card_number device_id]} {
+    log 0 "ERROR: Failed to parse hw string: $hw_string"
+}
+
+set pcm_status_file "/proc/asound/card${card_number}/pcm${device_id}${direction}/sub0/status"
+
+if {![file exists $pcm_status_file]} {
+    log 0 "ERROR: PCM status file not found: $pcm_status_file"
+    exit 1
+}
+
 spawn  {*}$argv
 set start_time_ms [clock milliseconds]; # re-adjust
 set last_space_time 0 ; # could not resist that name
@@ -218,6 +241,25 @@ expect {
                 log 1 "($pauses_counter/$repeat_count) Found volume ### | __%, active for $_record_for ms"
 
                 set _delay [substract_time_since_last_space $_record_for]
+
+                # wait 50ms for the PCM status to be RUNNING before pausing
+                # this is to make sure that in the case of an xrun the application
+                # successfully recovers and restarts the stream.
+                set max_attempts 50
+                set attempt 0
+                while {$attempt < $max_attempts} {
+                    set pcm_status [exec cat $pcm_status_file]
+                    if {[regexp {state:\s*RUNNING} $pcm_status]} {
+                        break
+                    }
+                    incr attempt
+                    after 1
+                }
+                if {$attempt >= $max_attempts} {
+                    log 0 "ERROR: timeout waiting for PCM status to be RUNNING before pause"
+                    exit 1
+                }
+
                 after $_delay "press_space; set state pause_requested"
                 log 3 "last_space_time=$last_space_time; timer in $_delay"