Amit Sunil Dhamne 2909f0d499 usb: typec: tcpm: reset internal port states on soft reset AMS
Reset internal port states (such as vdm_sm_running and
explicit_contract) on soft reset AMS as the port needs to negotiate a
new contract. The consequence of leaving the states in as-is cond are as
follows:
  * port is in SRC power role and an explicit contract is negotiated
    with the port partner (in sink role)
  * port partner sends a Soft Reset AMS while VDM State Machine is
    running
  * port accepts the Soft Reset request and the port advertises src caps
  * port partner sends a Request message but since the explicit_contract
    and vdm_sm_running are true from previous negotiation, the port ends
    up sending Soft Reset instead of Accept msg.

Stub Log:
[  203.653942] AMS DISCOVER_IDENTITY start
[  203.653947] PD TX, header: 0x176f
[  203.655901] PD TX complete, status: 0
[  203.657470] PD RX, header: 0x124f [1]
[  203.657477] Rx VDM cmd 0xff008081 type 2 cmd 1 len 1
[  203.657482] AMS DISCOVER_IDENTITY finished
[  203.657484] cc:=4
[  204.155698] PD RX, header: 0x144f [1]
[  204.155718] Rx VDM cmd 0xeeee8001 type 0 cmd 1 len 1
[  204.155741] PD TX, header: 0x196f
[  204.157622] PD TX complete, status: 0
[  204.160060] PD RX, header: 0x4d [1]
[  204.160066] state change SRC_READY -> SOFT_RESET [rev2 SOFT_RESET_AMS]
[  204.160076] PD TX, header: 0x163
[  204.162486] PD TX complete, status: 0
[  204.162832] AMS SOFT_RESET_AMS finished
[  204.162840] cc:=4
[  204.162891] AMS POWER_NEGOTIATION start
[  204.162896] state change SOFT_RESET -> AMS_START [rev2 POWER_NEGOTIATION]
[  204.162908] state change AMS_START -> SRC_SEND_CAPABILITIES [rev2 POWER_NEGOTIATION]
[  204.162913] PD TX, header: 0x1361
[  204.165529] PD TX complete, status: 0
[  204.165571] pending state change SRC_SEND_CAPABILITIES -> SRC_SEND_CAPABILITIES_TIMEOUT @ 60 ms [rev2 POWER_NEGOTIATION]
[  204.166996] PD RX, header: 0x1242 [1]
[  204.167009] state change SRC_SEND_CAPABILITIES -> SRC_SOFT_RESET_WAIT_SNK_TX [rev2 POWER_NEGOTIATION]
[  204.167019] AMS POWER_NEGOTIATION finished
[  204.167020] cc:=4
[  204.167083] AMS SOFT_RESET_AMS start
[  204.167086] state change SRC_SOFT_RESET_WAIT_SNK_TX -> SOFT_RESET_SEND [rev2 SOFT_RESET_AMS]
[  204.167092] PD TX, header: 0x16d
[  204.168824] PD TX complete, status: 0
[  204.168854] pending state change SOFT_RESET_SEND -> HARD_RESET_SEND @ 60 ms [rev2 SOFT_RESET_AMS]
[  204.171876] PD RX, header: 0x43 [1]
[  204.171879] AMS SOFT_RESET_AMS finished

This causes COMMON.PROC.PD.11.2 check failure for
TEST.PD.VDM.SRC.2_Rev2Src test on the PD compliance tester.

Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
Fixes: 8d3a0578ad ("usb: typec: tcpm: Respond Wait if VDM state machine is running")
Fixes: f0690a25a1 ("staging: typec: USB Type-C Port Manager (tcpm)")
Cc: stable <stable@kernel.org>
Reviewed-by: Badhri Jagan Sridharan <badhri@google.com>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://patch.msgid.link/20260414-fix-soft-reset-v1-1-01d7cb9764e2@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-27 09:49:43 -06:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2026-04-26 14:19:00 -07:00

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
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

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

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros
* AI Coding Assistant - LLMs and AI-powered development tools


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

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst

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
kernel:

* Documentation/process/coding-assistants.rst

This documentation contains essential requirements about licensing, attribution,
and the Developer Certificate of Origin that all AI tools must comply with.


Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst
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