From: Kyle Tso kyletso@google.com
commit f41bfc7e9c7c1d721c8752f1853cde43e606ad43 upstream.
In USB PD Spec Rev 3.1 Ver 1.0, section "6.12.5 Applicability of Structured VDM Commands", DFP is allowed and recommended to respond to Discovery Identity with ACK. And in section "6.4.4.2.5.1 Commands other than Attention", NAK should be returned only when receiving Messages with invalid fields, Messages in wrong situation, or unrecognize Messages.
Still keep the original design for SVDM Version 1.0 for backward compatibilities.
Fixes: 193a68011fdc ("staging: typec: tcpm: Respond to Discover Identity commands") Acked-by: Heikki Krogerus heikki.krogerus@linux.intel.com Signed-off-by: Kyle Tso kyletso@google.com Link: https://lore.kernel.org/r/20210601123151.3441914-2-kyletso@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/typec/tcpm/tcpm.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
--- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -1531,19 +1531,25 @@ static int tcpm_pd_svdm(struct tcpm_port if (PD_VDO_VID(p[0]) != USB_SID_PD) break;
- if (PD_VDO_SVDM_VER(p[0]) < svdm_version) + if (PD_VDO_SVDM_VER(p[0]) < svdm_version) { typec_partner_set_svdm_version(port->partner, PD_VDO_SVDM_VER(p[0])); + svdm_version = PD_VDO_SVDM_VER(p[0]); + }
tcpm_ams_start(port, DISCOVER_IDENTITY); - /* 6.4.4.3.1: Only respond as UFP (device) */ - if (port->data_role == TYPEC_DEVICE && + /* + * PD2.0 Spec 6.10.3: respond with NAK as DFP (data host) + * PD3.1 Spec 6.4.4.2.5.1: respond with NAK if "invalid field" or + * "wrong configuation" or "Unrecognized" + */ + if ((port->data_role == TYPEC_DEVICE || svdm_version >= SVDM_VER_2_0) && port->nr_snk_vdo) { /* * Product Type DFP and Connector Type are not defined in SVDM * version 1.0 and shall be set to zero. */ - if (typec_get_negotiated_svdm_version(typec) < SVDM_VER_2_0) + if (svdm_version < SVDM_VER_2_0) response[1] = port->snk_vdo[0] & ~IDH_DFP_MASK & ~IDH_CONN_MASK; else