Amit Sunil Dhamne cd3b9cea67 usb: typec: tcpm: constrain TCPM_SOURCING_VBUS event handling
When a sink detach occurs while waiting for TX send status, the old
TCPM_SOURCING_VBUS event along with TCPM_VBUS_EVENT and TCPM_CC_EVENT
can be queued in port->pd_events. Because TCPM_SOURCING_VBUS is
evaluated after TCPM_VBUS_EVENT and TCPM_CC_EVENT in
tcpm_pd_event_handler(), a stale TCPM_SOURCING_VBUS event can override
the detach handling and incorrectly set port->vbus_source and
port->vbus_present to true.

Add a state guard to check that the port is either operating as a
Source (tcpm_port_is_source(port)) or in a Fast Role Swap (FRS) state
up to FR_SWAP_SNK_SRC_SOURCE_VBUS_APPLIED before processing
TCPM_SOURCING_VBUS. Otherwise, discard and log the event.

Log snippet for error condition before fix:
[72792.204955] state change SRC_ATTACHED -> SRC_STARTUP [rev3 NONE_AMS]
[72792.204960] sourcing vbus
[72792.204962] VBUS on
[72792.204970] AMS POWER_NEGOTIATION start
[72792.204974] cc:=4
[72792.205319] state change SRC_STARTUP -> AMS_START [rev3 POWER_NEGOTIATION]
[72792.205325] state change AMS_START -> SRC_SEND_CAPABILITIES [rev3 POWER_NEGOTIATION]
[72792.205332] PD TX, header: 0x11a1
[72792.216911] PD TX complete, status: 2
[72792.216957] pending state change SRC_SEND_CAPABILITIES -> SRC_SEND_CAPABILITIES @ 150 ms [rev3 POWER_NEGOTIATION]
[72792.218005] VBUS off
[72792.218013] pending state change SRC_SEND_CAPABILITIES -> SNK_UNATTACHED @ 650 ms [rev3 POWER_NEGOTIATION]
[72792.218020] VBUS VSAFE0V
[72792.218024] state change SRC_SEND_CAPABILITIES -> SNK_UNATTACHED [rev3 POWER_NEGOTIATION]
[72792.218458] CC1: 2 -> 0, CC2: 0 -> 0 [state SNK_UNATTACHED, polarity 0, disconnected]
[72792.218467] VBUS on --> VBUS left on
[72792.218980] disable vbus discharge ret:0
[72792.235193] Start toggling

After fix:
[ 1195.291691] state change SRC_ATTACHED -> SRC_STARTUP [rev3 NONE_AMS]
[ 1195.291698] sourcing vbus
[ 1195.291700] VBUS on
[ 1195.291707] AMS POWER_NEGOTIATION start
[ 1195.291710] cc:=4
[ 1195.291758] state change SRC_STARTUP -> AMS_START [rev3 POWER_NEGOTIATION]
[ 1195.291794] state change AMS_START -> SRC_SEND_CAPABILITIES [rev3 POWER_NEGOTIATION]
[ 1195.291798] PD TX, header: 0x11a1
[ 1195.297056] PD TX complete, status: 2
[ 1195.297092] pending state change SRC_SEND_CAPABILITIES -> SRC_SEND_CAPABILITIES @ 150 ms [rev3 POWER_NEGOTIATION]
[ 1195.297177] VBUS off
[ 1195.297184] pending state change SRC_SEND_CAPABILITIES -> SNK_UNATTACHED @ 650 ms [rev3 POWER_NEGOTIATION]
[ 1195.297227] CC1: 2 -> 0, CC2: 0 -> 0 [state SRC_SEND_CAPABILITIES, polarity 0, disconnected]
[ 1195.307469] cc:=2
[ 1195.307544] pending state change SRC_SEND_CAPABILITIES -> SNK_UNATTACHED @ 650 ms [rev3 POWER_NEGOTIATION]
[ 1195.307555] Discarding sourcing vbus! Invalid state SRC_SEND_CAPABILITIES
[ 1195.957636] state change SRC_SEND_CAPABILITIES -> SNK_UNATTACHED [delayed 650 ms]
[ 1195.957732] disable vbus discharge ret:0
[ 1195.970196] Start toggling
[ 1195.970468] VBUS off
[ 1196.051637] VBUS off
[ 1196.051642] VBUS VSAFE0V

Fixes: 8dc4bd0736 ("usb: typec: tcpm: Add support for Sink Fast Role SWAP(FRS)")
Cc: stable <stable@kernel.org>
Assisted-by: Gemini:gemini-3.1-pro
Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
Reviewed-by: Badhri Jagan Sridharan <badhri@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20260827-sourcing-vbus-v1-1-9be1aca991a0@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-08-31 18:44:47 +02:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2026-08-30 13:34:40 -07:00
2026-07-15 10:51:29 -06:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
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* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

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* Building requirements: Documentation/process/changes.rst
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* License: See COPYING

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============

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For Specific Users
==================

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--------------------

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-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
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---------------

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-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
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--------------------

Configure, tune, and troubleshoot Linux systems:

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----------

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* Maintainer Handbook: Documentation/maintainer/index.rst
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---------------

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-----------------------

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* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
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AI Coding Assistant
-------------------

CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and
follow the AI coding assistants documentation before contributing to the Linux
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* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
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=========================

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