usb: typec: tpcm: Fix issues with power being removed during reset

Since the merge of b717dfbf73e8 ("Revert "usb: typec: tcpm: fix
cc role at port reset"") into mainline the LibreTech Renegade
Elite/Firefly has died during boot, the main symptom observed in testing
is a sudden stop in console output.  Gábor Stefanik identified in review
that the patch would cause power to be removed from devices without
batteries (like this board), observing that while the patch is correct
according to the spec this appears to be an oversight in the spec.

Given that the change makes previously working systems unusable let's
revert it, there was some discussion of identifying systems that have
alternative power and implementing the standards conforming behaviour in
only that case.

Fixes: b717dfbf73e8 ("Revert "usb: typec: tcpm: fix cc role at port reset"")
Cc: stable <stable@kernel.org>
Cc: Badhri Jagan Sridharan <badhri@google.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240212-usb-fix-renegade-v1-1-22c43c88d635@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 295ae7eb912c8da587c0fc03c51ae93a3993c517..66e532edcece68a713e9ebe7355e3cda38b9e465 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4873,7 +4873,8 @@ static void run_state_machine(struct tcpm_port *port)
                break;
        case PORT_RESET:
                tcpm_reset_port(port);
-               tcpm_set_cc(port, TYPEC_CC_OPEN);
+               tcpm_set_cc(port, tcpm_default_state(port) == SNK_UNATTACHED ?
+                           TYPEC_CC_RD : tcpm_rp_cc(port));
                tcpm_set_state(port, PORT_RESET_WAIT_OFF,
                               PD_T_ERROR_RECOVERY);
                break;