[syncd] TH4 - syncd is not up during init

[rkdevi27]

Issue:-
Trying to bring up TH4-BCM56990 platform (Dell Z9664) and syncd got exited.
Attaching the complete syslog and config.yml file used.
syslog.zip
th4-z9664f-64x400G.config.zip

[wdoekes]

Relevant subset from your syslog:

2024 Nov 13 12:12:44.960024 sonic INFO syncd#supervisord: syncd rc: BCM driver initialized#015
2024 Nov 13 12:12:44.960499 sonic INFO syncd#supervisord: syncd rc: Port modes initialized#015
2024 Nov 13 12:12:44.977828 sonic INFO syncd#syncd: [none] SAI_API_SWITCH:brcm_sai_create_switch:1495 SAI Timing: SDK init time 1 seconds
2024 Nov 13 12:12:44.978146 sonic INFO syncd#supervisord: syncd rc: platform SDK init complete#015
2024 Nov 13 12:12:45.032089 sonic INFO syncd#syncd: [none] SAI_API_SWITCH:brcm_sai_create_switch:1562 SAI MMU programming will be optimized
2024 Nov 13 12:12:45.067274 sonic INFO syncd#syncd: [none] SAI_API_BUFFER:_brcm_sai_mmu_retain_mmu_settings_on_speed_change:4536 Do not reset MMU settings on port speed change
2024 Nov 13 12:12:45.067274 sonic INFO syncd#syncd: [none] SAI_API_SWITCH:brcm_sai_create_switch:3093 Alpm default data mode = 1
2024 Nov 13 12:12:45.067274 sonic INFO syncd#syncd: [none] SAI_API_SWITCH:_brcm_sai_split_horizon_asic_fn_init:183 Split horizon table setting is not needed
2024 Nov 13 12:12:45.067379 sonic INFO syncd#syncd: [none] SAI_API_SWITCH:_brcm_sai_dev_features_init:1178 Switch mac tnl term enable = 0
2024 Nov 13 12:12:45.067379 sonic INFO syncd#syncd: [none] SAI_API_SWITCH:_brcm_sai_dev_features_init:1188 Svi tcam opt setting = 1
2024 Nov 13 12:12:45.067529 sonic INFO syncd#syncd: [none] SAI_API_PORT:_brcm_sai_dev_features_init:2699 Disable FP ports when switch shutdown.
2024 Nov 13 12:12:45.067985 sonic INFO syncd#syncd: [none] SAI_API_BUFFER:driverMMUInit:987 Set CPU Tx queue to cosq 7
2024 Nov 13 12:12:45.080576 sonic INFO syncd#syncd: [none] SAI_API_TAM:_brcm_sai_eapp_config_init:892 There is no Embedded apps configuration.
2024 Nov 13 12:12:45.080576 sonic CRIT syncd#syncd: [none] SAI_API_SWITCH:brcm_sai_create_switch:3206 setting inter-frame gap failed with error Feature unavailable (0xfffffff0).
2024 Nov 13 12:12:45.080576 sonic ERR syncd#syncd: :- sendApiResponse: api SAI_COMMON_API_CREATE failed in syncd mode: SAI_STATUS_NOT_SUPPORTED
2024 Nov 13 12:12:45.080840 sonic ERR syncd#syncd: :- processQuadEvent: attr: SAI_SWITCH_ATTR_INIT_SWITCH: true
2024 Nov 13 12:12:45.080840 sonic ERR syncd#syncd: :- processQuadEvent: attr: SAI_SWITCH_ATTR_FDB_EVENT_NOTIFY: 0x559fe0498680
2024 Nov 13 12:12:45.080840 sonic ERR syncd#syncd: :- processQuadEvent: attr: SAI_SWITCH_ATTR_PORT_STATE_CHANGE_NOTIFY: 0x559fe0498690
2024 Nov 13 12:12:45.080840 sonic ERR syncd#syncd: :- processQuadEvent: attr: SAI_SWITCH_ATTR_SWITCH_SHUTDOWN_REQUEST_NOTIFY: 0x559fe04986c0
2024 Nov 13 12:12:45.080840 sonic ERR syncd#syncd: :- processQuadEvent: attr: SAI_SWITCH_ATTR_SRC_MAC_ADDRESS: E8:B2:65:41:3A:30
2024 Nov 13 12:12:45.081288 sonic ERR swss#orchagent: :- create: create status: SAI_STATUS_NOT_SUPPORTED
2024 Nov 13 12:12:45.081288 sonic ERR swss#orchagent: :- main: Failed to create a switch, rv:-2
2024 Nov 13 12:12:45.081288 sonic NOTICE swss#orchagent: :- notifySyncd: sending syncd: SYNCD_INVOKE_DUMP
2024 Nov 13 12:12:45.081539 sonic NOTICE syncd#syncd: :- processNotifySyncd: Invoking SAI failure dump
2024 Nov 13 12:12:45.088445 sonic NOTICE swss#orchagent: :- sai_redis_notify_syncd: invoked DUMP succeeded

Alas, not the same problem I had in PR 3377.

[wdoekes]

This looks like your issue though:
sonic-net/sonic-buildimage#19749