David Lechner 79a86a6cc3 iio: orientation: hid-sensor-rotation: add timestamp hack to not break userspace
Add a hack to push two timestamps in the hid-sensor-rotation scan data
to avoid breaking userspace applications that depend on the timestamp
being at the incorrect location in the scan data due to unintentional
misalignment in older kernels.

When this driver was written, the timestamp was in the correct location
because of the way iio_compute_scan_bytes() was implemented at the time.
(Samples were 24 bytes each.) Then commit 883f616530 ("iio: buffer:
align the size of scan bytes to size of the largest element") changed
the computed scan_bytes to be a different size (32 bytes), which caused
iio_push_to_buffers_with_timestamp() to place the timestamp at an
incorrect offset.

There have been long periods of time (6 years each) where the timestamp
was in either location, so to not break either case, we open-code the
timestamps to be pushed to both locations in the scan data.

Reported-by: Jonathan Cameron <jic23@kernel.org>
Closes: https://lore.kernel.org/linux-iio/20260215162351.79f40b32@jic23-huawei/
Fixes: 883f616530 ("iio: buffer: align the size of scan bytes to size of the largest element")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2026-03-14 12:15:58 +00:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2026-02-22 13:18:59 -08:00

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/

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

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* Building requirements: Documentation/process/changes.rst
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============

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

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

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
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* Core APIs: Documentation/core-api/index.rst

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

Explore the kernel's architecture and internals:

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

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

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* 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

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

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
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Maintainer
----------

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

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* 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
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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
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.


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

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