What is the purpose of this commit

[Grubby0624]

hostboot/src/import/chips/ocmb/common/procedures/hwp/pmic/lib/utils/pmic_enable_utils.C

Line 476 in 1e3984c

FAPI_TRY(mss::pmic::i2c::reg_write(i_pmic_target, TPS_REGS::RA3_BREADCRUMB, CLEAR_BREAD_CRUMBS));

I have a few questions about this commit: 43fd55aa243fe570b989da8f8ff9fcb893c7d218 "Added recovery procedure to DDR4 pmic_n_made_detect":
1. What is the purpose of this commit? If I don't add this commit and restart the machine after setting the PMIC output voltage bias, it can start up normally. However, if I add this commit, the I2C link to this PMIC will report an I2C No ACK error after booting up
2. I am using TPS53830 PMIC, and I understand that RA3 represents the I2C address for this model of PMIC. Why is its value changed to 0x00 here?
Thanks!!

[dcrowell77]

I think there was a typo in your commit hash above. Did you mean 43fd55a? If so, the commit is adding some logic to recover a dead PMIC at runtime. It has been working fine for us. Where in the IPL do you see the failure?

I'm asking around about the second question. If that is a different PMIC model than we use then our code may not support it. In our case RA3 seems to be just a scratch register with no functional use.

[dcrowell77]

Are you testing with DDIMMs or some other configuration? Do you have DDR4 or DDR5 memory? It appears that you are going down a DDR4 code path using a PMIC that we only support on the DDR5 DDIMMs. There are some implicit assumptions about which PMIC models are supported for which DDR versions that you seem to be violating.