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Message-ID: <20251016055332.914106-1-acelan.kao@canonical.com>
Date: Thu, 16 Oct 2025 13:53:32 +0800
From: "Chia-Lin Kao (AceLan)" <acelan.kao@...onical.com>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
Fedor Pchelkin <boddah8794@...il.com>,
Andrei Kuchynski <akuchynski@...omium.org>,
Venkat Jayaraman <venkat.jayaraman@...el.com>,
Myrrh Periwinkle <myrrhperiwinkle@...labs.xyz>,
"Chia-Lin Kao (AceLan)" <acelan.kao@...onical.com>,
linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] usb: typec: ucsi: Detect and skip duplicate altmodes from buggy firmware
Some firmware implementations incorrectly return the same altmode
multiple times at different offsets when queried via UCSI_GET_ALTERNATE_MODES.
This causes sysfs duplicate filename errors and kernel call traces when
the driver attempts to register the same altmode twice:
sysfs: cannot create duplicate filename '/devices/.../typec/port0/port0.0/partner'
typec-thunderbolt port0-partner.1: failed to create symlinks
typec-thunderbolt port0-partner.1: probe with driver typec-thunderbolt failed with error -17
Detect duplicate altmodes by comparing SVID and VDO before registration.
If a duplicate is detected, skip it and print a single clean warning
message instead of generating a kernel call trace:
ucsi_acpi USBC000:00: con0: Firmware bug: duplicate partner altmode SVID 0x8087 at offset 1, ignoring. Please update your system firmware.
This makes the error handling more user-friendly while still alerting
users to the firmware bug.
The fix applies to all three recipient types: partner (SOP), port (CON),
and plug (SOP_P) altmodes.
Fixes: a79f16efcd00 ("usb: typec: ucsi: Add support for the partner USB Modes")
Cc: stable@...r.kernel.org
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@...onical.com>
---
drivers/usb/typec/ucsi/ucsi.c | 81 +++++++++++++++++++++++++++++++++++
1 file changed, 81 insertions(+)
diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 3f568f790f39..ebe7e0a223d7 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -602,9 +602,90 @@ static int ucsi_register_altmodes(struct ucsi_connector *con, u8 recipient)
i += num;
for (j = 0; j < num; j++) {
+ bool duplicate = false;
+ int k;
+
if (!alt[j].svid)
return 0;
+ /*
+ * Check if this altmode is already registered or is a duplicate
+ * within the current batch.
+ * Some firmware implementations incorrectly return the same
+ * altmode multiple times, either:
+ * 1. At different offsets in separate queries
+ * 2. Within the same query response (in alt[] array)
+ * Both cause sysfs duplicate errors during registration.
+ *
+ * We check for duplicates by comparing SVID and VDO (mid),
+ * which uniquely identify an altmode. If we find a match,
+ * skip registration to avoid kernel errors.
+ */
+
+ /* Check for duplicates in current batch first */
+ for (k = 0; k < j; k++) {
+ if (alt[k].svid == alt[j].svid && alt[k].mid == alt[j].mid) {
+ dev_warn_once(con->ucsi->dev,
+ "con%d: Firmware bug: duplicate altmode SVID 0x%04x in same response at offset %d, ignoring. Please update your system firmware.\n",
+ con->num, alt[j].svid, i - num + j);
+ duplicate = true;
+ break;
+ }
+ }
+
+ if (duplicate)
+ continue;
+
+ /* Check for duplicates in already registered altmodes */
+ if (recipient == UCSI_RECIPIENT_SOP) {
+ for (k = 0; k < UCSI_MAX_ALTMODES; k++) {
+ if (!con->partner_altmode[k])
+ break;
+ /*
+ * Some buggy firmware returns the same SVID multiple times
+ * with different VDOs. This causes duplicate device registration
+ * and sysfs errors. Check SVID only for partner altmodes.
+ */
+ if (con->partner_altmode[k]->svid == alt[j].svid) {
+ dev_warn(con->ucsi->dev,
+ "con%d: Firmware bug: duplicate partner altmode SVID 0x%04x (VDO 0x%08x vs 0x%08x) at offset %d, ignoring. Please update your system firmware.\n",
+ con->num, alt[j].svid, con->partner_altmode[k]->vdo,
+ alt[j].mid, i - num + j);
+ duplicate = true;
+ break;
+ }
+ }
+ } else if (recipient == UCSI_RECIPIENT_CON) {
+ for (k = 0; k < UCSI_MAX_ALTMODES; k++) {
+ if (!con->port_altmode[k])
+ break;
+ if (con->port_altmode[k]->svid == alt[j].svid &&
+ con->port_altmode[k]->vdo == alt[j].mid) {
+ dev_warn_once(con->ucsi->dev,
+ "con%d: Firmware bug: duplicate port altmode SVID 0x%04x at offset %d, ignoring. Please update your system firmware.\n",
+ con->num, alt[j].svid, i - num + j);
+ duplicate = true;
+ break;
+ }
+ }
+ } else if (recipient == UCSI_RECIPIENT_SOP_P) {
+ for (k = 0; k < UCSI_MAX_ALTMODES; k++) {
+ if (!con->plug_altmode[k])
+ break;
+ if (con->plug_altmode[k]->svid == alt[j].svid &&
+ con->plug_altmode[k]->vdo == alt[j].mid) {
+ dev_warn_once(con->ucsi->dev,
+ "con%d: Firmware bug: duplicate plug altmode SVID 0x%04x at offset %d, ignoring. Please update your system firmware.\n",
+ con->num, alt[j].svid, i - num + j);
+ duplicate = true;
+ break;
+ }
+ }
+ }
+
+ if (duplicate)
+ continue;
+
memset(&desc, 0, sizeof(desc));
desc.vdo = alt[j].mid;
desc.svid = alt[j].svid;
--
2.43.0
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