diff options
Diffstat (limited to 'common/usbc/usb_pe_drp_sm.c')
| -rw-r--r-- | common/usbc/usb_pe_drp_sm.c | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/common/usbc/usb_pe_drp_sm.c b/common/usbc/usb_pe_drp_sm.c index ab481bffe5..9a764cb716 100644 --- a/common/usbc/usb_pe_drp_sm.c +++ b/common/usbc/usb_pe_drp_sm.c @@ -182,11 +182,23 @@ #define N_DISCOVER_IDENTITY_COUNT 6 /* - * tDiscoverIdentity is only defined while an explicit contract is in place. - * To support captive cable devices that power the SOP' responder from VBUS - * instead of VCONN stretch out the SOP' Discover Identity messages when - * no contract is present. 200 ms provides about 1 second for the cable - * to power up (200 * 5 retries). + * It is permitted to send SOP' Discover Identity messages before a PD contract + * is in place. However, this is only beneficial if the cable powers up quickly + * solely from VCONN. Limit the number of retries without a contract to + * ensure we attempt some cable discovery after a contract is in place. + */ +#define N_DISCOVER_IDENTITY_PRECONTRACT_LIMIT 2 + +/* + * Once this limit of SOP' Discover Identity messages has been set, downgrade + * to PD 2.0 in case the cable is non-compliant about GoodCRC-ing higher + * revisions. This limit should be higher than the precontract limit. + */ +#define N_DISCOVER_IDENTITY_PD3_0_LIMIT 4 + +/* + * tDiscoverIdentity is only defined while an explicit contract is in place, so + * extend the interval between retries pre-contract. */ #define PE_T_DISCOVER_IDENTITY_NO_CONTRACT (200*MSEC) @@ -1946,7 +1958,9 @@ static void pe_src_discovery_run(int port) */ if (pd_get_identity_discovery(port, TCPC_TX_SOP_PRIME) == PD_DISC_NEEDED && get_time().val > pe[port].discover_identity_timer - && pe_can_send_sop_prime(port)) { + && pe_can_send_sop_prime(port) + && (pe[port].discover_identity_counter < + N_DISCOVER_IDENTITY_PRECONTRACT_LIMIT)) { pe[port].tx_type = TCPC_TX_SOP_PRIME; set_state_pe(port, PE_VDM_IDENTITY_REQUEST_CBL); return; @@ -2209,7 +2223,6 @@ static void pe_src_transition_supply_run(int port) if (PE_CHK_FLAG(port, PE_FLAGS_PS_READY)) { PE_CLR_FLAG(port, PE_FLAGS_PS_READY); - /* NOTE: Second pass through this code block */ /* * Set first message flag to trigger a wait and add @@ -2219,6 +2232,7 @@ static void pe_src_transition_supply_run(int port) if (!pe_is_explicit_contract(port)) PE_SET_FLAG(port, PE_FLAGS_FIRST_MSG); + /* NOTE: Second pass through this code block */ /* Explicit Contract is now in place */ pe_set_explicit_contract(port); @@ -5068,10 +5082,10 @@ static void pe_vdm_identity_request_cbl_exit(int port) pd_set_identity_discovery(port, pe[port].tx_type, PD_DISC_FAIL); else if (pe[port].discover_identity_counter == - (N_DISCOVER_IDENTITY_COUNT / 2)) + N_DISCOVER_IDENTITY_PD3_0_LIMIT) /* - * Downgrade to PD 2.0 if the partner hasn't replied halfway - * through discovery as well, in case the cable is + * Downgrade to PD 2.0 if the partner hasn't replied before + * all retries are exhausted in case the cable is * non-compliant about GoodCRC-ing higher revisions */ prl_set_rev(port, TCPC_TX_SOP_PRIME, PD_REV20); |