Now I tried to capture USB PD signals using a peeled USB-C cable and a logic analyzer:
Seems like the laptop does not ack to the message asking about battery capability.
And tried to send soft reset, but no response
Finally a hard reset message is observed, and that’s probably what causes to power cycle
On comparison with Dell XPS, it acks the message and returns that this feature is unsupported.
I cannot upload sigrok capture here, so I am putting it on my Google Drive. The log also comes with other captures to a charger and to a desktop PC. EDIT: To make fair comparison, I added USB-PD capture for a Dell XPS 13 to iPhone 15 Pro Max into the zip file
Hopefully someone with USB-PD knowhow knows what is happening here.
EDIT2: turns out sigrok decoder GitHub - sigrokproject/libsigrokdecode: Read-only mirror of the official repo at git://sigrok.org/libsigrokdecode. Pull requests welcome. Please file bugreports at sigrok.org/bugzilla. is not able to decode USB PD Revision 3.2 properly, as some of the extended data are wrongly decoded. I am trying to work on the decoder so it is updated to the standard.
EDIT3: updated with the partially patched sigrok decoder