On 8/17/21 2:36 AM, Heikki Krogerus wrote:
On Fri, Aug 13, 2021 at 12:31:31PM +0800, Icenowy Zheng wrote:Currently, TCPM code omits discover when swapping to gadget, and assume that no altmodes are available when swapping from gadget. However, we do send discover when we get attached as gadget -- this leads to modes to be discovered twice when attached as gadget and then swap to host. Always re-send discover when swapping DR, regardless of what change is being made; and because of this, the assumption that no altmodes are registered with gadget role is broken, and altmodes de-registeration is always needed now. Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx> --- drivers/usb/typec/tcpm/tcpm.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index b9bb63d749ec..ab6d0d51ee1c 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -4495,15 +4495,14 @@ static void run_state_machine(struct tcpm_port *port) tcpm_set_state(port, ready_state(port), 0); break; case DR_SWAP_CHANGE_DR: - if (port->data_role == TYPEC_HOST) { - tcpm_unregister_altmodes(port); + tcpm_unregister_altmodes(port); + if (port->data_role == TYPEC_HOST) tcpm_set_roles(port, true, port->pwr_role, TYPEC_DEVICE); - } else { + else tcpm_set_roles(port, true, port->pwr_role, TYPEC_HOST); - port->send_discover = true; - } + port->send_discover = true; tcpm_ams_finish(port); tcpm_set_state(port, ready_state(port), 0); break;Why is it necessary to do discovery with data role swap in general? thanks,
Additional question: There are two patches pending related to DR_SWAP and discovery. Are they both needed, or do they both solve the same problem ? Thanks, Guenter
