diff options
Diffstat (limited to 'include/uapi/linux/input.h')
| -rw-r--r-- | include/uapi/linux/input.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/uapi/linux/input.h b/include/uapi/linux/input.h index a8e74b45dbe2..4f9f2a0f5573 100644 --- a/include/uapi/linux/input.h +++ b/include/uapi/linux/input.h @@ -414,6 +414,14 @@ struct ff_effect { #define FF_GAIN 0x60 #define FF_AUTOCENTER 0x61 +/* + * ff->playback(effect_id = FF_GAIN) is the first effect_id to + * cause a collision with another ff method, in this case ff->set_gain(). + * Therefore the greatest safe value for effect_id is FF_GAIN - 1, + * and thus the total number of effects should never exceed FF_GAIN. + */ +#define FF_MAX_EFFECTS FF_GAIN + #define FF_MAX 0x7f #define FF_CNT (FF_MAX+1) |