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| author |   Peter Hutterer <peter.hutterer@who-t.net> | 2018-12-05 10:42:23 +1000 |
|---|---|---|
| committer |   Benjamin Tissoires <benjamin.tissoires@redhat.com> | 2018-12-07 16:27:13 +0100 |
| commit | 5a4abb36f312cf83206b1b7d1308ba47cba0b3cc (patch) | |
| tree | 928db9e1b26c88b5bda3247ebdf3b8858628c88b /include/linux/hid.h | |
| parent | HID: core: store the collections as a basic tree (diff) | |
| download | linux-dev-5a4abb36f312cf83206b1b7d1308ba47cba0b3cc.tar.xz linux-dev-5a4abb36f312cf83206b1b7d1308ba47cba0b3cc.zip | |
HID: core: process the Resolution Multiplier
The Resolution Multiplier is a feature report that modifies the value of
Usages within the same Logical Collection. If the multiplier is set to
anything but 1, the hardware reports (value * multiplier) for the same amount
of physical movement, i.e. the value we receive in the kernel is
pre-multiplied.
The hardware may either send a single (value * multiplier), or by sending
multiplier as many reports with the same value, or a combination of these two
options. For example, when the Microsoft Sculpt Ergonomic mouse Resolution
Multiplier is set to 12, the Wheel sends out 12 for every detent but AC Pan
sends out a value of 3 at 4 times the frequency.
The effective multiplier is based on the physical min/max of the multiplier
field, a logical min/max of [0,1] with a physical min/max of [1,8] means the
multiplier is either 1 or 8.
The Resolution Multiplier was introduced for high-resolution scrolling in
Windows Vista and is commonly used on Microsoft mice.
The recommendation for the Resolution Multiplier is to default to 1 for
backwards compatibility. This patch adds an arbitrary upper limit at 255. The
only known use case for the Resolution Multiplier is for scroll wheels where the
multiplier has to be a fraction of 120 to work with Windows.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Verified-by: Harry Cutts <hcutts@chromium.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Diffstat (limited to 'include/linux/hid.h')
| -rw-r--r-- | include/linux/hid.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/hid.h b/include/linux/hid.h index fdfda898656c..fd8d860365a4 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -219,6 +219,7 @@ struct hid_item { #define HID_GD_VBRZ 0x00010045 #define HID_GD_VNO 0x00010046 #define HID_GD_FEATURE 0x00010047 +#define HID_GD_RESOLUTION_MULTIPLIER 0x00010048 #define HID_GD_SYSTEM_CONTROL 0x00010080 #define HID_GD_UP 0x00010090 #define HID_GD_DOWN 0x00010091 @@ -437,6 +438,8 @@ struct hid_usage { unsigned hid; /* hid usage code */ unsigned collection_index; /* index into collection array */ unsigned usage_index; /* index into usage array */ + __s8 resolution_multiplier;/* Effective Resolution Multiplier + (HUT v1.12, 4.3.1), default: 1 */ /* hidinput data */ __u16 code; /* input driver code */ __u8 type; /* input driver type */ @@ -894,6 +897,8 @@ struct hid_report *hid_validate_values(struct hid_device *hid, unsigned int type, unsigned int id, unsigned int field_index, unsigned int report_counts); + +void hid_setup_resolution_multiplier(struct hid_device *hid); int hid_open_report(struct hid_device *device); int hid_check_keys_pressed(struct hid_device *hid); int hid_connect(struct hid_device *hid, unsigned int connect_mask); |