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Diffstat (limited to 'Documentation/input/event-codes.rst')
| -rw-r--r-- | Documentation/input/event-codes.rst | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst index cef220c176a4..b24b5343f5eb 100644 --- a/Documentation/input/event-codes.rst +++ b/Documentation/input/event-codes.rst @@ -190,16 +190,26 @@ A few EV_REL codes have special meanings: * REL_WHEEL, REL_HWHEEL: - These codes are used for vertical and horizontal scroll wheels, - respectively. The value is the number of "notches" moved on the wheel, the - physical size of which varies by device. For high-resolution wheels (which - report multiple events for each notch of movement, or do not have notches) - this may be an approximation based on the high-resolution scroll events. - -* REL_WHEEL_HI_RES: - - - If a vertical scroll wheel supports high-resolution scrolling, this code - will be emitted in addition to REL_WHEEL. The value is the (approximate) - distance travelled by the user's finger, in microns. + respectively. The value is the number of detents moved on the wheel, the + physical size of which varies by device. For high-resolution wheels + this may be an approximation based on the high-resolution scroll events, + see REL_WHEEL_HI_RES. These event codes are legacy codes and + REL_WHEEL_HI_RES and REL_HWHEEL_HI_RES should be preferred where + available. + +* REL_WHEEL_HI_RES, REL_HWHEEL_HI_RES: + + - High-resolution scroll wheel data. The accumulated value 120 represents + movement by one detent. For devices that do not provide high-resolution + scrolling, the value is always a multiple of 120. For devices with + high-resolution scrolling, the value may be a fraction of 120. + + If a vertical scroll wheel supports high-resolution scrolling, this code + will be emitted in addition to REL_WHEEL or REL_HWHEEL. The REL_WHEEL + and REL_HWHEEL may be an approximation based on the high-resolution + scroll events. There is no guarantee that the high-resolution data + is a multiple of 120 at the time of an emulated REL_WHEEL or REL_HWHEEL + event. EV_ABS ------ |