Sven Peter 7d55b44e2b phy: apple: atc: Actually check return value of devm_apple_tunable_parse
Let's actually check the return value of devm_apple_tunable_parse
instead of trying to check IS_ERR on a pointer to the return value which
is always going to be valid. This prevent a oops when the tunables are
invalid or when they don't exist:

[   57.664567] Unable to handle kernel paging request at virtual address fffffffffffffffe
[   57.664584] Mem abort info:
[   57.664589]   ESR = 0x0000000096000007
[   57.664595]   EC = 0x25: DABT (current EL), IL = 32 bits
[   57.664602]   SET = 0, FnV = 0
[   57.664607]   EA = 0, S1PTW = 0
[   57.664611]   FSC = 0x07: level 3 translation fault
[   57.664617] Data abort info:
[   57.664621]   ISV = 0, ISS = 0x00000007, ISS2 = 0x00000000
[   57.664626]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[   57.664631]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[   57.664640] swapper pgtable: 16k pages, 47-bit VAs, pgdp=0000000b4391c000
[   57.664647] [fffffffffffffffe] pgd=0000000000000000, p4d=0000000000000000, pud=0000000b44188403, pmd=0000000b4418c403, pte=0000000000000000
[   57.664670] Internal error: Oops: 0000000096000007 [#1]  SMP
[   57.665047] CPU: 1 UID: 0 PID: 23 Comm: kworker/1:0 Tainted: G S                  6.18.2+ #2 PREEMPTLAZY
[   57.665061] Tainted: [S]=CPU_OUT_OF_SPEC
[   57.665066] Hardware name: Apple Mac mini (M1, 2020) (DT)
[   57.665072] Workqueue: events cd321x_update_work [tps6598x]
[   57.665100] pstate: 61400009 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[   57.665111] pc : apple_tunable_apply+0x8/0x80 [apple_tunable]
[   57.665121] lr : atcphy_mux_set+0x3e0/0x1138 [phy_apple_atc]
[   57.665133] sp : ffffc000802a7c00
[   57.665138] x29: ffffc000802a7c00 x28: 0000000000000003 x27: ffff800016c84080
[   57.665151] x26: 0000000000000002 x25: ffff800016c84090 x24: ffff800016c8408f
[   57.665163] x23: 0000000000020004 x22: 0000000000000001 x21: 0000000000000006
[   57.665175] x20: ffff80000d6da9b0 x19: ffff80000d6da880 x18: 0000000000000002
[   57.665188] x17: 0000000000000000 x16: ffffe22de59e0e38 x15: 0000000000000002
[   57.665199] x14: ffffe22de76ecff8 x13: 0000000000000001 x12: ffff9dd5f90bc000
[   57.665211] x11: 00000000000000c0 x10: 048abc15ceba0919 x9 : ffffe22dbc5fde10
[   57.665223] x8 : ffff80000175e0d8 x7 : 0000000000000004 x6 : 0000000000000000
[   57.665234] x5 : 0000000000000001 x4 : 0000000d6d132db7 x3 : 00000000000155db
[   57.665246] x2 : 0000000000000000 x1 : fffffffffffffffe x0 : ffffc00082b80000
[   57.665258] Call trace:
[   57.665265]  apple_tunable_apply+0x8/0x80 [apple_tunable] (P)
[   57.665276]  typec_mux_set+0x74/0xe0 [typec]
[   57.665315]  cd321x_update_work+0x440/0x8c0 [tps6598x]
[   57.665332]  process_one_work+0x178/0x3d0
[   57.665346]  worker_thread+0x260/0x390
[   57.665354]  kthread+0x150/0x250
[   57.665369]  ret_from_fork+0x10/0x20
[   57.665386] Code: e69a0ae8 ffffe22d aa1e03e9 d503201f (f9400022)
[   57.665394] ---[ end trace 0000000000000000 ]---

Reported-by: Thomas Glanzmann <thomas@glanzmann.de>
Fixes: 8e98ca1e74 ("phy: apple: Add Apple Type-C PHY")
Signed-off-by: Sven Peter <sven@kernel.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20260104-atcphy-tunable-fix-v2-1-84e5c2a57aaa@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2026-01-14 19:42:53 +05:30
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2025-12-14 16:05:07 +12:00

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


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



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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