Re: [PATCH 3/5] ipmi: ssif_bmc: fix message desynchronization after truncated response

[Quan Nguyen]

On 2/4/26 18:04, Jian Zhang wrote:
> A truncated response, caused by host power-off, or other conditions,
> can lead to message desynchronization.
>
> Raw trace data (STOP loss scenario, add state transition comment):
>
> 1. T-1: Read response phase (SSIF_RES_SENDING)
> 8271.955342  WR_RCV [03]                          <- Read polling cmd
> 8271.955348  RD_REQ [04]  <== SSIF_RES_SENDING    <- start sending response
> 8271.955436  RD_PRO [b4]
> 8271.955527  RD_PRO [00]
> 8271.955618  RD_PRO [c1]
> 8271.955707  RD_PRO [00]
> 8271.955814  RD_PRO [ad]  <== SSIF_RES_SENDING     <- last byte
> 	<- !! STOP lost (truncated response)

Honestly, I have a little concern about if there is the case. What I 
think is that if there was no ACK (SCA is not pull low by Controller) on 
the 9th clock pulse while Target sending data to bus. Target will 
release SDA line, eventually, there will be a STOP condition and a 
SLAVE_STOP event should be emitted.

- Quan