Re: [PATCH v2] Documentation: Add evdev type and code definitions

[Dmitry Torokhov]

Hi Chase,

On Fri, Jan 07, 2011 at 04:28:15PM -0500, Chase Douglas wrote:
> +
> +* KEY_SUSPEND, KEY_POWER:
> +  - These codes are reserved for the EV_PWR type.
> +

This is not correct, KEY_SUSPEND and KEY_POWER are valid events for
EV_KEY type. We need to figure out what to do with drivers who like to do
EV_PWR/KEY_PWR though.

The whole EV_PWR business is iffy. IIRC/IIUC it was envisioned to semd
powwer events _to_ the devices to implement device-level PM. We'll have
to revisit it at some point.


> +EV_REL:
> +----------
> +EV_REL events describe relative changes in a property. For example, a mouse may
> +move to the left by a certain number of units, but its absolute position in
> +space is unknown. If the absolute position is known, EV_ABS codes should be used
> +instead of EV_REL codes.
> +
> +A few EV_REL codes have special meanings:
> +
> +* REL_WHEEL, REL_HWHEEL:
> +  - These codes are used for vertical and horizontal scroll wheels,
> +    respectively.
> +
> +EV_ABS:
> +----------
> +EV_ABS events describe absolute changes in a property. For example, a touchpad
> +may emit coordinates for a touch location.
> +
> +A few EV_ABS codes have special meanings:
> +
> +* ABS_DISTANCE:
> +  - Used to describe the distance of a tool from an interaction surface. This
> +    should only be used while the tool is hovering, meaning in close proximity
> +    of the device. If the input device may be used freely in three dimensions,
> +    consider ABS_Z instead.
> +
> +* ABS_MT_<name>:
> +  - Used to describe multitouch input events. Please see
> +    multi-touch-protocol.txt for details.
> +
> +EV_SW:
> +----------
> +EV_SW events describe stateful binary switches. For example, the SW_LID code is
> +used to denote when a laptop lid is closed.

Please add that drivers should refresh switch state upon binding to a
device and also upon resume.

> +
> +EV_MSC:
> +----------
> +EV_MSC events are used for input and output events that do not fall under other
> +categories.
> +
> +EV_LED:
> +----------
> +EV_LED events are used for input and output to set and query the state of
> +various LEDs on devices.
> +
> +EV_REP:
> +----------
> +EV_REP events are used for specifying autorepeating events.
> +
> +EV_SND:
> +----------
> +EV_SND events are used for sending sound commands to simple sound output
> +devices.
> +
> +EV_FF:
> +----------
> +EV_FF events are used to initialize a force feedback capable device and to cause
> +such device to feedback.
> +
> +EV_PWR:
> +----------
> +EV_PWR events are a special type of key event used specifically for monitoring
> +power buttons and switches. The two codes in use are:
> +
> +* KEY_POWER:
> +  - Used to denote a power button event.
> +
> +* KEY_SUSPEND:
> +  - Used to denote a suspend button event.

Just replace this with TBA for now.

Thanks.

-- 
Dmitry
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