From: Li Jun jun.li@nxp.com
commit 2d9c6442a9c81f4f8dee678d0b3c183173ab1e2d upstream.
Current tcpm_detach() only reset hard_reset_count if port->attached is true, this may cause this counter clear is missed if the CC disconnect event is generated after tcpm_port_reset() is done by other events, e.g. VBUS off comes first before CC disconect for a power sink, in that case the first tcpm_detach() will only clear port->attached flag but leave hard_reset_count there because tcpm_port_is_disconnected() is still false, then later tcpm_detach() by CC disconnect will directly return due to port->attached is cleared, finally this will result tcpm will not try hard reset or error recovery for later attach.
ChiYuan reported this issue on his platform with below tcpm trace: After power sink session setup after hard reset 2 times, detach from the power source and then attach: [ 4848.046358] VBUS off [ 4848.046384] state change SNK_READY -> SNK_UNATTACHED [ 4848.050908] Setting voltage/current limit 0 mV 0 mA [ 4848.050936] polarity 0 [ 4848.052593] Requesting mux state 0, usb-role 0, orientation 0 [ 4848.053222] Start toggling [ 4848.086500] state change SNK_UNATTACHED -> TOGGLING [ 4848.089983] CC1: 0 -> 0, CC2: 3 -> 3 [state TOGGLING, polarity 0, connected] [ 4848.089993] state change TOGGLING -> SNK_ATTACH_WAIT [ 4848.090031] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @200 ms [ 4848.141162] CC1: 0 -> 0, CC2: 3 -> 0 [state SNK_ATTACH_WAIT, polarity 0, disconnected] [ 4848.141170] state change SNK_ATTACH_WAIT -> SNK_ATTACH_WAIT [ 4848.141184] pending state change SNK_ATTACH_WAIT -> SNK_UNATTACHED @20 ms [ 4848.163156] state change SNK_ATTACH_WAIT -> SNK_UNATTACHED [delayed 20 ms] [ 4848.163162] Start toggling [ 4848.216918] CC1: 0 -> 0, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected] [ 4848.216954] state change TOGGLING -> SNK_ATTACH_WAIT [ 4848.217080] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @200 ms [ 4848.231771] CC1: 0 -> 0, CC2: 3 -> 0 [state SNK_ATTACH_WAIT, polarity 0, disconnected] [ 4848.231800] state change SNK_ATTACH_WAIT -> SNK_ATTACH_WAIT [ 4848.231857] pending state change SNK_ATTACH_WAIT -> SNK_UNATTACHED @20 ms [ 4848.256022] state change SNK_ATTACH_WAIT -> SNK_UNATTACHED [delayed20 ms] [ 4848.256049] Start toggling [ 4848.871148] VBUS on [ 4848.885324] CC1: 0 -> 0, CC2: 0 -> 3 [state TOGGLING, polarity 0, connected] [ 4848.885372] state change TOGGLING -> SNK_ATTACH_WAIT [ 4848.885548] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @200 ms [ 4849.088240] state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED [delayed200 ms] [ 4849.088284] state change SNK_DEBOUNCED -> SNK_ATTACHED [ 4849.088291] polarity 1 [ 4849.088769] Requesting mux state 1, usb-role 2, orientation 2 [ 4849.088895] state change SNK_ATTACHED -> SNK_STARTUP [ 4849.088907] state change SNK_STARTUP -> SNK_DISCOVERY [ 4849.088915] Setting voltage/current limit 5000 mV 0 mA [ 4849.088927] vbus=0 charge:=1 [ 4849.090505] state change SNK_DISCOVERY -> SNK_WAIT_CAPABILITIES [ 4849.090828] pending state change SNK_WAIT_CAPABILITIES -> SNK_READY @240 ms [ 4849.335878] state change SNK_WAIT_CAPABILITIES -> SNK_READY [delayed240 ms]
this patch fix this issue by clear hard_reset_count at any cases of cc disconnect, í.e. don't check port->attached flag.
Fixes: 4b4e02c83167 ("typec: tcpm: Move out of staging") Cc: stable@vger.kernel.org Reported-and-tested-by: ChiYuan Huang cy_huang@richtek.com Reviewed-by: Guenter Roeck linux@roeck-us.net Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com Signed-off-by: Li Jun jun.li@nxp.com Link: https://lore.kernel.org/r/1602500592-3817-1-git-send-email-jun.li@nxp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/typec/tcpm.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/usb/typec/tcpm.c +++ b/drivers/usb/typec/tcpm.c @@ -2727,12 +2727,12 @@ static void tcpm_reset_port(struct tcpm_
static void tcpm_detach(struct tcpm_port *port) { - if (!port->attached) - return; - if (tcpm_port_is_disconnected(port)) port->hard_reset_count = 0;
+ if (!port->attached) + return; + tcpm_reset_port(port); }