libinput/quirks/README.md

libinput quirks file format
===========================

This directory contains hardware quirks used by libinput to work around bugs
in the hardware, device behavior and to supply information not obtained
through the kernel device.

**THIS IS NOT STABLE API**

The data format may change at any time. If your quirks file is not part of
the libinput git tree, do not expect it to work after an update. Absolutely
no guarantees are made for backwards-compatibility.

**THIS IS NOT A CONFIGURATION API**

Use the `libinput_device_config_foo()` functions for device configuration.
Quirks here are hardware quirks only.

Data file naming
----------------

Data files are read in versionsort order, read order determines how values
override each other. Values read later override previously read values. The
current structure is:
- `10-generic-foo.quirks` for generic settings,
- `30-vendor-foo.quirks` for vendor-specific settings, and
- `50-system-foo.quirks` for system vendors.

This is not a fixed naming scheme and may change at any time. It's an
approximation only because some vendors are also system vendors, e.g.
Microsoft makes devices and laptops.

Laptop-specific quirks should always go into the laptop vendor's file even
where they apply to a component of a different vendor. For example, a quirk
for a Synaptics touchpad specific to a Dell laptop should go into the Dell
quirks file.

Sections, matches and values
----------------------------

A data file must contain at least one section, each section must have at
least one `Match` tag and at least one of either `Attr` or `Model`. Section
names are free-form and may contain spaces.

```
# This is a comment
[Some touchpad]
MatchBus=usb
# No quotes around strings
MatchName=*Synaptics Touchpad*
AttrSizeHint=50x50
ModelSynapticsTouchpad=1

[Apple touchpad]
MatchVendor=0x5AC
MatchProduct=0x123
ModelAppleTouchpad=1
```

Comments are lines starting with `#`.

All `Model` tags take a value of either `1` or `0`.

All `Attr` tag values are specific to that attribute.

Parser errors
-------------

The following requirements must be met:

* No whitespace is allowed at the beginning of the line
* A Section must have at least one `Match*` entry
* A Section must not repeat `Match*` entry
* A Section must have at least one of `Model*` or `Attr*` entries
* A `Model` tag may only have the value `1` or `0`
* String properties must not be enclosed in quotes
* Hex numbers must use uppercase letters (e.g. `0x12AB`)

Failure to meet these requirements will cause a parser error and the quirks
files will not be used.

Debugging
---------

When modifying a data file, use the `libinput list-quirks` tool to
verify the changes. The tool can be pointed at the data directory to
analyse, use `--verbose` to get more info. For example:

```
libinput list-quirks --data-dir /path/to/git/repo/quirks/ --verbose /dev/input/event0
```