diff options
Diffstat (limited to 'common')
| -rw-r--r-- | common/usb_pd_protocol.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c index 039ef9dc23..e06d424c39 100644 --- a/common/usb_pd_protocol.c +++ b/common/usb_pd_protocol.c @@ -102,7 +102,15 @@ static const int debug_level; * going to, but not so long that a "low power charger connected" notification * would be shown in the chrome OS UI. */ -#define READY_HOLD_OFF_US (200 * MSEC) +#define SNK_READY_HOLD_OFF_US (200 * MSEC) +/* + * For the same purpose as SNK_READY_HOLD_OFF_US, but this delay can be longer + * since the concern over "low power charger" is not relevant when connected as + * a source and the additional delay avoids a race condition where the partner + * port sends a power role swap request close to when the VDM discover identity + * message gets sent. + */ +#define SRC_READY_HOLD_OFF_US (400 * MSEC) enum vdm_states { VDM_STATE_ERR_BUSY = -3, @@ -1842,7 +1850,7 @@ static void handle_ctrl_request(int port, uint16_t head, */ if (pd[port].task_state == PD_STATE_SNK_TRANSITION) pd[port].ready_state_holdoff_timer = - get_time().val + READY_HOLD_OFF_US + get_time().val + SNK_READY_HOLD_OFF_US + (get_time().le.lo % (100 * MSEC)); set_state(port, PD_STATE_SNK_READY); @@ -3577,10 +3585,14 @@ void pd_task(void *u) * before we may send messages of our own. Add * some jitter of up to 100ms, taken from the * current system time, to prevent multiple - * collisions. + * collisions. This delay also allows the sink + * device to request power role swap and allow + * the the accept message to be sent prior to + * CMD_DISCOVER_IDENT being sent in the + * SRC_READY state. */ pd[port].ready_state_holdoff_timer = - get_time().val + READY_HOLD_OFF_US + get_time().val + SRC_READY_HOLD_OFF_US + (get_time().le.lo % (100 * MSEC)); /* it'a time to ping regularly the sink */ |