From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198

---
 kernel/drivers/usb/typec/altmodes/displayport.c |   34 +++++++++++++++++++++++++++-------
 1 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/kernel/drivers/usb/typec/altmodes/displayport.c b/kernel/drivers/usb/typec/altmodes/displayport.c
index 8769cab..bcc1db4 100644
--- a/kernel/drivers/usb/typec/altmodes/displayport.c
+++ b/kernel/drivers/usb/typec/altmodes/displayport.c
@@ -114,8 +114,12 @@
 		if (dp->data.status & DP_STATUS_PREFER_MULTI_FUNC &&
 		    pin_assign & DP_PIN_ASSIGN_MULTI_FUNC_MASK)
 			pin_assign &= DP_PIN_ASSIGN_MULTI_FUNC_MASK;
-		else if (pin_assign & DP_PIN_ASSIGN_DP_ONLY_MASK)
+		else if (pin_assign & DP_PIN_ASSIGN_DP_ONLY_MASK) {
 			pin_assign &= DP_PIN_ASSIGN_DP_ONLY_MASK;
+			/* Default to pin assign C if available */
+			if (pin_assign & BIT(DP_PIN_ASSIGN_C))
+				pin_assign = BIT(DP_PIN_ASSIGN_C);
+		}
 
 		/*
 		 * DFP_U never selects Pin Assignment E when Pin Assignment C
@@ -444,6 +448,18 @@
 	[DP_PIN_ASSIGN_F] = "F",
 };
 
+/*
+ * Helper function to extract a peripheral's currently supported
+ * Pin Assignments from its DisplayPort alternate mode state.
+ */
+static u8 get_current_pin_assignments(struct dp_altmode *dp)
+{
+	if (DP_CONF_CURRENTLY(dp->data.conf) == DP_CONF_DFP_D)
+		return DP_CAP_PIN_ASSIGN_DFP_D(dp->alt->vdo);
+	else
+		return DP_CAP_PIN_ASSIGN_UFP_D(dp->alt->vdo);
+}
+
 static ssize_t
 pin_assignment_store(struct device *dev, struct device_attribute *attr,
 		     const char *buf, size_t size)
@@ -470,7 +486,7 @@
 		goto out_unlock;
 	}
 
-	assignments = DP_CAP_PIN_ASSIGN(dp->alt->vdo);
+	assignments = get_current_pin_assignments(dp);
 
 	if (!(DP_CONF_GET_PIN_ASSIGN(conf) & assignments)) {
 		ret = -EINVAL;
@@ -507,7 +523,7 @@
 
 	cur = get_count_order(DP_CONF_GET_PIN_ASSIGN(dp->data.conf));
 
-	assignments = DP_CAP_PIN_ASSIGN(dp->alt->vdo);
+	assignments = get_current_pin_assignments(dp);
 
 	for (i = 0; assignments; assignments >>= 1, i++) {
 		if (assignments & 1) {
@@ -521,6 +537,10 @@
 	}
 
 	mutex_unlock(&dp->lock);
+
+	/* get_current_pin_assignments can return 0 when no matching pin assignments are found */
+	if (len == 0)
+		len++;
 
 	buf[len - 1] = '\n';
 	return len;
@@ -548,10 +568,10 @@
 	/* FIXME: Port can only be DFP_U. */
 
 	/* Make sure we have compatiple pin configurations */
-	if (!(DP_CAP_DFP_D_PIN_ASSIGN(port->vdo) &
-	      DP_CAP_UFP_D_PIN_ASSIGN(alt->vdo)) &&
-	    !(DP_CAP_UFP_D_PIN_ASSIGN(port->vdo) &
-	      DP_CAP_DFP_D_PIN_ASSIGN(alt->vdo)))
+	if (!(DP_CAP_PIN_ASSIGN_DFP_D(port->vdo) &
+	      DP_CAP_PIN_ASSIGN_UFP_D(alt->vdo)) &&
+	    !(DP_CAP_PIN_ASSIGN_UFP_D(port->vdo) &
+	      DP_CAP_PIN_ASSIGN_DFP_D(alt->vdo)))
 		return -ENODEV;
 
 	ret = sysfs_create_group(&alt->dev.kobj, &dp_altmode_group);

--
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