Fix IPL monitor failure

The I2C bus on which the FPGA resides is somewhat noisy / high traffic.  This leads to frequent i2cget failures.
Retry a failed FPGA register access up to 16 times before aborting.

1 files changed, 9 insertions, 27 deletions

diff --git a/pyiplledmonitor/ipl_status_led_monitor.py b/pyiplledmonitor/ipl_status_led_monitor.py
index ac3d6ad..a67186a 100644
--- a/pyiplledmonitor/ipl_status_led_monitor.py
+++ b/pyiplledmonitor/ipl_status_led_monitor.py
@@ -67,34 +67,11 @@ class IPLStatusLEDMonitor(DbusProperties, DbusObjectManager):
         print "IPLStatusLEDMonitor Init Done"
 
     def IPLLEDReadI2CByte(self, byte):
+        retry_number = 0
         retval = 0
-        comm_fail = False;
-        try:
-            proc = subprocess.Popen(["i2cget", "-y", "12", "0x31", str(byte)], stdout=subprocess.PIPE, stderr=open(os.devnull, 'wb'), shell=False)
-            (out, err) = proc.communicate()
-            if (proc.returncode != 0):
-                comm_fail = True
-            else:
-                retval = int(out, 16)
-        except:
-            comm_fail = True;
-            pass
-        if (comm_fail == True):
-            comm_fail = False
-            time.sleep(1)
-            try:
-                proc = subprocess.Popen(["i2cget", "-y", "12", "0x31", str(byte)], stdout=subprocess.PIPE, stderr=open(os.devnull, 'wb'), shell=False)
-                (out, err) = proc.communicate()
-                if (proc.returncode != 0):
-                    comm_fail = True
-                else:
-                    retval = int(out, 16)
-            except:
-                comm_fail = True;
-                pass
-        if (comm_fail == True):
-            comm_fail = False
-            time.sleep(1)
+        comm_fail = True;
+        while (comm_fail == True):
+            comm_fail = False;
             try:
                 proc = subprocess.Popen(["i2cget", "-y", "12", "0x31", str(byte)], stdout=subprocess.PIPE, stderr=open(os.devnull, 'wb'), shell=False)
                 (out, err) = proc.communicate()
@@ -105,6 +82,11 @@ class IPLStatusLEDMonitor(DbusProperties, DbusObjectManager):
             except:
                 comm_fail = True;
                 pass
+            if (comm_fail == True):
+                retry_number += 1
+                if (retry_number > 16):
+                    break
+                time.sleep(0.1)
         return retval
 
     def IPLLEDCheckSystem(self):