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Commit c4be61c3 authored by Jack Pham's avatar Jack Pham
Browse files

usb: pd: Avoid blocking wait in SRC_TRANSITION_TO_DEFAULT 



When sending/receiving a hard reset in source mode, the
PE_SRC_TRANSITION_TO_DEFAULT state turns off VBUS/VCONN and
sleeps for 750ms. During this fairly long period any Type-C
event such as cable disconnect or reconnect won't get
processed as the workqueue is blocked by this wait condition.
This can lead to incorrect state handling, for example when
a sink is removed and a source is attached; the state machine
will think a sink is still attached. Fix this by removing
the msleep() and set a timer to restart the state machine
to PE_UNKNOWN which will turn VBUS/VCONN back on and start
again in PE_SRC_STARTUP. This frees up the workqueue to
process any potential incoming events in the meantime.

Change-Id: I282551a58252a672f319d1559eac9f4ad4c3ca8a
Signed-off-by: default avatarJack Pham <jackp@codeaurora.org>
parent be0f20ce

drivers/usb/pd/policy_engine.c

+10 −18
Original line number Diff line number Diff line
@@ -2053,6 +2053,10 @@ static void usbpd_sm(struct work_struct *w) 


	switch (pd->current_state) {

	case PE_UNKNOWN:

		val.intval = 0;

		power_supply_set_property(pd->usb_psy,

				POWER_SUPPLY_PROP_PD_IN_HARD_RESET, &val);



		if (pd->current_pr == PR_SINK) {

			usbpd_set_state(pd, PE_SNK_STARTUP);

		} else if (pd->current_pr == PR_SRC) {
@@ -2215,8 +2219,11 @@ static void usbpd_sm(struct work_struct *w) 
	case PE_SRC_TRANSITION_TO_DEFAULT:

		if (pd->vconn_enabled)

			regulator_disable(pd->vconn);

		pd->vconn_enabled = false;



		if (pd->vbus_enabled)

			regulator_disable(pd->vbus);

		pd->vbus_enabled = false;



		if (pd->current_dr != DR_DFP) {

			extcon_set_state_sync(pd->extcon, EXTCON_USB, 0);
@@ -2224,24 +2231,9 @@ static void usbpd_sm(struct work_struct *w) 
			pd_phy_update_roles(pd->current_dr, pd->current_pr);

		}



		msleep(SRC_RECOVER_TIME);



		pd->vbus_enabled = false;

		enable_vbus(pd);



		if (pd->vconn_enabled) {

			ret = regulator_enable(pd->vconn);

			if (ret) {

				usbpd_err(&pd->dev, "Unable to enable vconn\n");

				pd->vconn_enabled = false;

			}

		}



		val.intval = 0;

		power_supply_set_property(pd->usb_psy,

				POWER_SUPPLY_PROP_PD_IN_HARD_RESET, &val);



		usbpd_set_state(pd, PE_SRC_STARTUP);

		/* PE_UNKNOWN will turn on VBUS and go back to PE_SRC_STARTUP */

		pd->current_state = PE_UNKNOWN;

		kick_sm(pd, SRC_RECOVER_TIME);

		break;



	case PE_SRC_HARD_RESET: