From 2dc702c991e3774af9d7ce410eef410ca9e2357e Mon Sep 17 00:00:00 2001 From: Peter Hutterer Date: Wed, 5 Dec 2018 10:42:24 +1000 Subject: HID: input: use the Resolution Multiplier for high-resolution scrolling Windows uses a magic number of 120 for a wheel click. High-resolution scroll wheels are supposed to use a fraction of 120 to signal smaller scroll steps. This is implemented by the Resolution Multiplier in the device itself. If the multiplier is present in the report descriptor, set it to the logical max and then use the resolution multiplier to calculate the high-resolution events. This is the recommendation by Microsoft, see http://msdn.microsoft.com/en-us/windows/hardware/gg487477.aspx Note that all mice encountered so far have a logical min/max of 0/1, so it's a binary "yes or no" to high-res scrolling anyway. To make userspace simpler, always enable the REL_WHEEL_HI_RES bit. Where the device doesn't support high-resolution scrolling, the value for the high-res data will simply be a multiple of 120 every time. For userspace, if REL_WHEEL_HI_RES is available that is the one to be used. Potential side-effect: a device with a Resolution Multiplier applying to other Input items will have those items set to the logical max as well. This cannot easily be worked around but it is doubtful such devices exist. Signed-off-by: Peter Hutterer Verified-by: Harry Cutts Signed-off-by: Benjamin Tissoires --- drivers/hid/hid-input.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 105 insertions(+), 3 deletions(-) (limited to 'drivers/hid') diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index d6fab5798487..59a5608b8dc0 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -712,7 +712,15 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel map_abs_clear(usage->hid & 0xf); break; - case HID_GD_SLIDER: case HID_GD_DIAL: case HID_GD_WHEEL: + case HID_GD_WHEEL: + if (field->flags & HID_MAIN_ITEM_RELATIVE) { + set_bit(REL_WHEEL, input->relbit); + map_rel(REL_WHEEL_HI_RES); + } else { + map_abs(usage->hid & 0xf); + } + break; + case HID_GD_SLIDER: case HID_GD_DIAL: if (field->flags & HID_MAIN_ITEM_RELATIVE) map_rel(usage->hid & 0xf); else @@ -1012,7 +1020,10 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel case 0x22f: map_key_clear(KEY_ZOOMRESET); break; case 0x233: map_key_clear(KEY_SCROLLUP); break; case 0x234: map_key_clear(KEY_SCROLLDOWN); break; - case 0x238: map_rel(REL_HWHEEL); break; + case 0x238: /* AC Pan */ + set_bit(REL_HWHEEL, input->relbit); + map_rel(REL_HWHEEL_HI_RES); + break; case 0x23d: map_key_clear(KEY_EDIT); break; case 0x25f: map_key_clear(KEY_CANCEL); break; case 0x269: map_key_clear(KEY_INSERT); break; @@ -1200,6 +1211,38 @@ ignore: } +static void hidinput_handle_scroll(struct hid_usage *usage, + struct input_dev *input, + __s32 value) +{ + int code; + int hi_res, lo_res; + + if (value == 0) + return; + + if (usage->code == REL_WHEEL_HI_RES) + code = REL_WHEEL; + else + code = REL_HWHEEL; + + /* + * Windows reports one wheel click as value 120. Where a high-res + * scroll wheel is present, a fraction of 120 is reported instead. + * Our REL_WHEEL_HI_RES axis does the same because all HW must + * adhere to the 120 expectation. + */ + hi_res = value * 120/usage->resolution_multiplier; + + usage->wheel_accumulated += hi_res; + lo_res = usage->wheel_accumulated/120; + if (lo_res) + usage->wheel_accumulated -= lo_res * 120; + + input_event(input, EV_REL, code, lo_res); + input_event(input, EV_REL, usage->code, hi_res); +} + void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value) { struct input_dev *input; @@ -1262,6 +1305,12 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct if ((usage->type == EV_KEY) && (usage->code == 0)) /* Key 0 is "unassigned", not KEY_UNKNOWN */ return; + if ((usage->type == EV_REL) && (usage->code == REL_WHEEL_HI_RES || + usage->code == REL_HWHEEL_HI_RES)) { + hidinput_handle_scroll(usage, input, value); + return; + } + if ((usage->type == EV_ABS) && (field->flags & HID_MAIN_ITEM_RELATIVE) && (usage->code == ABS_VOLUME)) { int count = abs(value); @@ -1489,6 +1538,58 @@ static void hidinput_close(struct input_dev *dev) hid_hw_close(hid); } +static void hidinput_change_resolution_multipliers(struct hid_device *hid) +{ + struct hid_report_enum *rep_enum; + struct hid_report *rep; + struct hid_usage *usage; + int i, j; + + rep_enum = &hid->report_enum[HID_FEATURE_REPORT]; + list_for_each_entry(rep, &rep_enum->report_list, list) { + bool update_needed = false; + + if (rep->maxfield == 0) + continue; + + /* + * If we have more than one feature within this report we + * need to fill in the bits from the others before we can + * overwrite the ones for the Resolution Multiplier. + */ + if (rep->maxfield > 1) { + hid_hw_request(hid, rep, HID_REQ_GET_REPORT); + hid_hw_wait(hid); + } + + for (i = 0; i < rep->maxfield; i++) { + __s32 logical_max = rep->field[i]->logical_maximum; + + /* There is no good reason for a Resolution + * Multiplier to have a count other than 1. + * Ignore that case. + */ + if (rep->field[i]->report_count != 1) + continue; + + for (j = 0; j < rep->field[i]->maxusage; j++) { + usage = &rep->field[i]->usage[j]; + + if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER) + continue; + + *rep->field[i]->value = logical_max; + update_needed = true; + } + } + if (update_needed) + hid_hw_request(hid, rep, HID_REQ_SET_REPORT); + } + + /* refresh our structs */ + hid_setup_resolution_multiplier(hid); +} + static void report_features(struct hid_device *hid) { struct hid_driver *drv = hid->driver; @@ -1782,6 +1883,8 @@ int hidinput_connect(struct hid_device *hid, unsigned int force) } } + hidinput_change_resolution_multipliers(hid); + list_for_each_entry_safe(hidinput, next, &hid->inputs, list) { if (drv->input_configured && drv->input_configured(hid, hidinput)) @@ -1840,4 +1943,3 @@ void hidinput_disconnect(struct hid_device *hid) cancel_work_sync(&hid->led_work); } EXPORT_SYMBOL_GPL(hidinput_disconnect); - -- cgit v1.2.1