ci/bare-metal: Truncate printed times and prefixes

The date isn't interesting, since you can tell if it wraps around
anyway. Just print the time down to the millisecond, which should be
plenty enough. We also don't need to print 'R SERIAL_CPU> ' when almost
every line is reading from the CPU serial buffer, so make that the
default.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31602>

.gitlab-ci/bare-metal/cros_servo_run.py

@@ -22,11 +22,11 @@ SECTION_END="end"
 class CrosServoRun:
     def __init__(self, cpu, ec, test_timeout, logger):
         self.cpu_ser = SerialBuffer(
-            cpu, "results/serial.txt", "R SERIAL-CPU> ")
+            cpu, "results/serial.txt", ": ")
         # Merge the EC serial into the cpu_ser's line stream so that we can
         # effectively poll on both at the same time and not have to worry about
         self.ec_ser = SerialBuffer(
-            ec, "results/serial-ec.txt", "R SERIAL-EC> ", line_queue=self.cpu_ser.line_queue)
+            ec, "results/serial-ec.txt", " EC: ", line_queue=self.cpu_ser.line_queue)
         self.test_timeout = test_timeout
         self.logger = logger
 
@@ -35,11 +35,11 @@ class CrosServoRun:
         self.cpu_ser.close()
 
     def ec_write(self, s):
-        print("W SERIAL-EC> %s" % s)
+        print("EC> %s" % s)
         self.ec_ser.serial.write(s.encode())
 
     def cpu_write(self, s):
-        print("W SERIAL-CPU> %s" % s)
+        print("> %s" % s)
         self.cpu_ser.serial.write(s.encode())
 
     def print_error(self, message):

.gitlab-ci/bare-metal/poe_run.py

@@ -35,7 +35,7 @@ class PoERun:
         self.powerup = args.powerup
         self.powerdown = args.powerdown
         self.ser = SerialBuffer(
-            args.dev, "results/serial-output.txt", "")
+            args.dev, "results/serial-output.txt", ": ")
         self.boot_timeout = boot_timeout
         self.test_timeout = test_timeout
         self.logger = logger

.gitlab-ci/bare-metal/serial_buffer.py

@@ -22,7 +22,7 @@
 # IN THE SOFTWARE.
 
 import argparse
-from datetime import datetime, timezone
+from datetime import datetime, UTC
 import queue
 import serial
 import threading
@@ -130,9 +130,10 @@ class SerialBuffer:
                 if b == b'\n'[0]:
                     line = line.decode(errors="replace")
 
-                    time = datetime.now().strftime('%y-%m-%d %H:%M:%S')
-                    print("{endc}{time} {prefix}{line}".format(
-                        time=time, prefix=self.prefix, line=line, endc='\033[0m'), flush=True, end='')
+                    ts = datetime.now(tz=UTC)
+                    ts_str = f"{ts.hour:02}:{ts.minute:02}:{ts.second:02}.{int(ts.microsecond / 1000):03}"
+                    print("{endc}{time}{prefix}{line}".format(
+                        time=ts_str, prefix=self.prefix, line=line, endc='\033[0m'), flush=True, end='')
 
                     self.line_queue.put(line)
                     line = bytearray()