feat(bmc): Re-enable bmc_monitor with an I2C write/read-back test

bmc_monitor.sh comes back into the run with a second job beyond the
`free -m` sampling: an I2C pattern test against bus 1, address 0x41,
offset 0x00C0 -- write 55AA55AA and read it back, then write AA55AA55
and read that back. Two complementary patterns catch a stuck bit either
way round, and repeating it through the soak turns an intermittent I2C
fault into something the log shows rather than something the tester has
to catch live.

Script B starts it alongside the other stress; Script C stops it and
cats log/bmc_poll.log.

bmc_monitor_ddr.sh stays disabled -- BMC DDR stress runs through
bgctl + bmc-manager.

Docs: the "disabled" notes I added last time now applied to only half
the pair and read as wrong for bmc_monitor.sh. Split so the monitor is
documented as live with its I2C test, and only the _ddr variant is
marked disabled.

Script A -> V1.0.8.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014RetWKFZFG1ZHcitQAyhwM

src/Script_ABC_Blanton/1_Blanton_Script_A.ttl

@@ -1,6 +1,6 @@
 ; =============================================================================
 ; Script A for Blanton
-; Version : V1.0.7
+; Version : V1.0.8
 ; Date    : 2026-08-25
 ; Author  : ETWen
 ; =============================================================================
@@ -43,6 +43,9 @@
 ;                       ScriptC                                         Copy stress jobs log to USB, timestamped
 ;                       utils/wait_init.ttl                             WT_INTERVAL 10 -> 60, fix WT_MIN comments
 ;                       ScriptC                                         Disable BMC USB journalctl dump
+;   V1.0.8  2026-08-25  Blanton_Script/bmc_monitor.sh                   Add BMC I2C write/read-back pattern test
+;                       ScriptB                                         Re-enable bmc_monitor.sh start
+;                       ScriptC                                         Re-enable bmc_monitor.sh stop + cat bmc_poll.log
 ; =============================================================================
 include "config.ttl"
 

src/Script_ABC_Blanton/2_Blanton_Script_B.ttl

@@ -28,6 +28,10 @@ sendln "~/hammer/tools/amd/mlucas-avx2 -s l -cpu 0:15 > ~/hammer/tools/amd/mluca
 wait prompt_sonic_root
 sendln "bgctl run bmc-manager run '/usr/bin/memtester 64M 1'"
 
+; ========== BMC Monitor Test ==========
+wait prompt_sonic_root
+sendln "./Blanton_Script/bmc_monitor.sh start"
+
 ; ========== DDR MEMORY STRESS TEST ==========
 wait prompt_sonic_root
 sendln "bgctl run /usr/sbin/memtester 1G 100"

src/Script_ABC_Blanton/3_Blanton_Script_C.ttl

@@ -53,6 +53,12 @@ sendln "/usr/sbin/ras-mc-ctl --summary"
 ;wait prompt_sonic_root
 ;sendln "cat ./Blanton_Script/log/bmc_ddr.log"
 
+; ========== BMC Monitor TAKE DATA ==========
+wait prompt_sonic_root
+sendln "./Blanton_Script/bmc_monitor.sh stop"
+wait prompt_sonic_root
+sendln "cat ./Blanton_Script/log/bmc_poll.log"
+
 ; ========== BMC USB Test result ==========
 ;wait prompt_sonic_root
 ;sendln "journalctl -u qfx5252-bmc-usb-net-test.service --no-pager"

src/Script_ABC_Blanton/Blanton_Script/bmc_monitor.sh

@@ -34,6 +34,10 @@ set -u
 # Add a line to add a command; comment it out to disable it.
 COMMANDS=(
     "free -m"
+    "i2ctransfer -f -y 1 w6@0x41 0x00 0xC0 0x55 0xAA 0x55 0xAA"
+    "i2ctransfer -f -y 1 w2@0x41 0x00 0xC0 r4"
+    "i2ctransfer -f -y 1 w6@0x41 0x00 0xC0 0xAA 0x55 0xAA 0x55"
+    "i2ctransfer -f -y 1 w2@0x41 0x00 0xC0 r4"
     #"uptime"
     #"cat /proc/loadavg"
     #"cat /proc/meminfo"