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| author | Caveh Jalali <caveh@chromium.org> | 2019-06-12 00:59:17 -0700 |
|---|---|---|
| committer | Commit Bot <commit-bot@chromium.org> | 2019-10-31 07:18:25 +0000 |
| commit | b0828291b501289f4c1d3726ab545cf3efd06d13 (patch) | |
| tree | 0709d8d4262fbdacb6b2897b08b9e405d3ebe8c8 /common | |
| parent | 85ae91a99c04bc77b9c4fd3159e04fa4e9d0af16 (diff) | |
| download | chrome-ec-b0828291b501289f4c1d3726ab545cf3efd06d13.tar.gz | |
pd_protocol: add hard_reset_complete_timer
certain chargers have noisy CC lines which can prevent overly
sensitive TCPCs from detecting a bus idle state. this means the TCPC
will not send out messages such as hard_reset. this condition may not
clear which means our pd_task() will retry sending hard_resets.
although we specify a "timeout" for the event loop in this state, the
timeout can be ignored by the event wait when there are pending
events. this gets us into a tight event processing loop that starves
the watchdog!
the solution is to add an explicit timeout timer when processing the
PD_STATE_HARD_RESET_SEND state.
BUG=b:134702480
BRANCH=none
TEST=no more EC watchdog on affected systems
Change-Id: I1ae871f5d8fc99f6906ddd18741bbf68dcb6e935
Signed-off-by: Caveh Jalali <caveh@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1889431
Tested-by: Nitin Kolluru <nkolluru@google.com>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Diffstat (limited to 'common')
| -rw-r--r-- | common/usb_pd_protocol.c | 68 |
1 files changed, 49 insertions, 19 deletions
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c index 77cb652a19..ad4ff19fa0 100644 --- a/common/usb_pd_protocol.c +++ b/common/usb_pd_protocol.c @@ -267,6 +267,11 @@ static struct pd_protocol { * of our own. */ uint64_t ready_state_holdoff_timer; + /* + * PD 2.0 spec, section 6.5.11.1 + * When we can give up on a HARD_RESET transmission. + */ + uint64_t hard_reset_complete_timer; } pd[CONFIG_USB_PD_PORT_COUNT]; #ifdef CONFIG_COMMON_RUNTIME @@ -4452,8 +4457,10 @@ void pd_task(void *u) break; case PD_STATE_HARD_RESET_SEND: hard_reset_count++; - if (pd[port].last_state != pd[port].task_state) + if (pd[port].last_state != pd[port].task_state) { hard_reset_sent = 0; + pd[port].hard_reset_complete_timer = 0; + } #ifdef CONFIG_CHARGE_MANAGER if (pd[port].last_state == PD_STATE_SNK_DISCOVERY || (pd[port].last_state == PD_STATE_SOFT_RESET && @@ -4473,29 +4480,52 @@ void pd_task(void *u) } #endif - /* try sending hard reset until it succeeds */ - if (!hard_reset_sent) { - if (pd_transmit(port, TCPC_TX_HARD_RESET, - 0, NULL) < 0) { - timeout = 10*MSEC; + if (hard_reset_sent) + break; + + if (pd_transmit(port, TCPC_TX_HARD_RESET, 0, NULL) < + 0) { + /* + * likely a non-idle channel + * TCPCI r2.0 v1.0 4.4.15: + * the TCPC does not retry HARD_RESET + * but we can try periodically until the timer + * expires. + */ + now = get_time(); + if (pd[port].hard_reset_complete_timer == 0) { + pd[port].hard_reset_complete_timer = + now.val + + PD_T_HARD_RESET_COMPLETE; + timeout = PD_T_HARD_RESET_RETRY; + break; + } + if (now.val < + pd[port].hard_reset_complete_timer) { + CPRINTS("C%d: Retrying hard reset", + port); + timeout = PD_T_HARD_RESET_RETRY; break; } - - /* successfully sent hard reset */ - hard_reset_sent = 1; /* - * If we are source, delay before cutting power - * to allow sink time to get hard reset. + * PD 2.0 spec, section 6.5.11.1 + * Pretend TX_HARD_RESET succeeded after + * timeout. */ - if (pd[port].power_role == PD_ROLE_SOURCE) { - set_state_timeout(port, - get_time().val + PD_T_PS_HARD_RESET, - PD_STATE_HARD_RESET_EXECUTE); - } else { - set_state(port, + } + + hard_reset_sent = 1; + /* + * If we are source, delay before cutting power + * to allow sink time to get hard reset. + */ + if (pd[port].power_role == PD_ROLE_SOURCE) { + set_state_timeout(port, + get_time().val + PD_T_PS_HARD_RESET, PD_STATE_HARD_RESET_EXECUTE); - timeout = 10*MSEC; - } + } else { + set_state(port, PD_STATE_HARD_RESET_EXECUTE); + timeout = 10 * MSEC; } break; case PD_STATE_HARD_RESET_EXECUTE: |