FAILED: patch "[PATCH] usb: typec: tcpm: Correct the responses in SVDM Version 2.0" failed to apply to 4.14-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f41bfc7e9c7c1d721c8752f1853cde43e606ad43 Mon Sep 17 00:00:00 2001
From: Kyle Tso <kyletso@google.com>
Date: Tue, 1 Jun 2021 20:31:48 +0800
Subject: [PATCH] usb: typec: tcpm: Correct the responses in SVDM Version 2.0
 DFP

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>

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 9ce8c9af4da5..a1bf0dc5babf 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -1547,19 +1547,25 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
 			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