From 8d55a12a9538742f510087f14fc59eb813b2ef42 Mon Sep 17 00:00:00 2001 From: Wojciech Siewierski Date: Tue, 8 Mar 2016 08:48:43 +0100 Subject: [PATCH] Document the issue of stuck modifiers --- README.md | 20 ++++++++++++++++++++ tmk_core/common/action.c | 2 +- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/README.md b/README.md index 6a6bbed40b..d8dfd7c2bc 100644 --- a/README.md +++ b/README.md @@ -98,6 +98,26 @@ We've added shortcuts to make common modifier/tap (mod-tap) mappings more compac `DF(layer)` - sets default layer to *layer*. The default layer is the one at the "bottom" of the layer stack - the ultimate fallback layer. This currently does not persist over power loss. When you plug the keyboard back in, layer 0 will always be the default. It is theoretically possible to work around that, but that's not what `DF` does. +### Prevent stuck modifiers + +Consider the following scenario: + +1. Layer 0 has a key defined as Shift. +2. The same key is defined on layer 1 as the letter A. +3. User presses Shift. +4. User switches to layer 1 for whatever reason. +5. User releases Shift, or rather the letter A. +6. User switches back to layer 0. + +Shift was actually never released and is still considered pressed. + +If such situation bothers you add this to your `config.h`: + + #define PREVENT_STUCK_MODIFIERS + +Warning: This option uses up 2 bytes of memory per key. For example on +Planck it uses 2\*4\*12=96 bytes. + ### Remember: These are just aliases These functions work the same way that their `ACTION_*` functions do - they're just quick aliases. To dig into all of the tmk ACTION_* functions, please see the [TMK documentation](https://github.com/jackhumbert/qmk_firmware/blob/master/tmk_core/doc/keymap.md#2-action). diff --git a/tmk_core/common/action.c b/tmk_core/common/action.c index be06e12aae..26a5fad7ac 100644 --- a/tmk_core/common/action.c +++ b/tmk_core/common/action.c @@ -61,7 +61,7 @@ void action_exec(keyevent_t event) */ action_t store_or_get_action(bool pressed, keypos_t key) { -#ifndef NO_ACTION_LAYER +#if !defined(NO_ACTION_LAYER) && defined(PREVENT_STUCK_MODIFIERS) static action_t pressed_actions[MATRIX_ROWS][MATRIX_COLS]; if (pressed) {