From 1c1813a743fe84d0dcf53743baa4edc1f74c44c8 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:15 +0100 Subject: HID: core: statically allocate read buffers This is a preparation patch for rethinking the generic processing of HID reports. We can actually pre-allocate all of our memory instead of dynamically allocating/freeing it whenever we parse a report. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-core.c | 12 +++++------- include/linux/hid.h | 1 + 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index f1aed5bbd000..75e7b8447bf7 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -101,7 +101,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned field = kzalloc((sizeof(struct hid_field) + usages * sizeof(struct hid_usage) + - usages * sizeof(unsigned)), GFP_KERNEL); + 2 * usages * sizeof(unsigned int)), GFP_KERNEL); if (!field) return NULL; @@ -109,6 +109,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned report->field[field->index] = field; field->usage = (struct hid_usage *)(field + 1); field->value = (s32 *)(field->usage + usages); + field->new_value = (s32 *)(field->value + usages); field->report = report; return field; @@ -1541,9 +1542,8 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, __s32 max = field->logical_maximum; __s32 *value; - value = kmalloc_array(count, sizeof(__s32), GFP_ATOMIC); - if (!value) - return; + value = field->new_value; + memset(value, 0, count * sizeof(__s32)); for (n = 0; n < count; n++) { @@ -1557,7 +1557,7 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, value[n] >= min && value[n] <= max && value[n] - min < field->maxusage && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) - goto exit; + return; } for (n = 0; n < count; n++) { @@ -1581,8 +1581,6 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, } memcpy(field->value, value, count * sizeof(__s32)); -exit: - kfree(value); } /* diff --git a/include/linux/hid.h b/include/linux/hid.h index 7487b0586fe6..3fbfe0986659 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -476,6 +476,7 @@ struct hid_field { unsigned report_count; /* number of this field in the report */ unsigned report_type; /* (input,output,feature) */ __s32 *value; /* last known value(s) */ + __s32 *new_value; /* newly read value(s) */ __s32 logical_minimum; __s32 logical_maximum; __s32 physical_minimum; -- cgit v1.2.3 From 74acc277b65219002bb103e51e461c2934563ada Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:16 +0100 Subject: HID: core: de-duplicate some code in hid_input_field() I had to go twice through the history to get a grasp at this code. De-duplicate the various tests in one common helper to make it more explicit. Note that the `HID_UP_KEYBOARD + 1` condition is tested through https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/121 Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-core.c | 54 ++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 39 insertions(+), 15 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 75e7b8447bf7..fad4dbdf6391 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1525,6 +1525,24 @@ static void hid_process_event(struct hid_device *hid, struct hid_field *field, hid->hiddev_hid_event(hid, field, usage, value); } +/* + * Checks if the given value is valid within this field + */ +static inline int hid_array_value_is_valid(struct hid_field *field, + __s32 value) +{ + __s32 min = field->logical_minimum; + + /* + * Value needs to be between logical min and max, and + * (value - min) is used as an index in the usage array. + * This array is of size field->maxusage + */ + return value >= min && + value <= field->logical_maximum && + value - min < field->maxusage; +} + /* * Analyse a received field, and fetch the data from it. The field * content is stored for next report processing (we do differential @@ -1539,7 +1557,6 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, unsigned offset = field->report_offset; unsigned size = field->report_size; __s32 min = field->logical_minimum; - __s32 max = field->logical_maximum; __s32 *value; value = field->new_value; @@ -1554,8 +1571,7 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, /* Ignore report if ErrorRollOver */ if (!(field->flags & HID_MAIN_ITEM_VARIABLE) && - value[n] >= min && value[n] <= max && - value[n] - min < field->maxusage && + hid_array_value_is_valid(field, value[n]) && field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) return; } @@ -1563,21 +1579,29 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, for (n = 0; n < count; n++) { if (HID_MAIN_ITEM_VARIABLE & field->flags) { - hid_process_event(hid, field, &field->usage[n], value[n], interrupt); + hid_process_event(hid, + field, + &field->usage[n], + value[n], + interrupt); continue; } - if (field->value[n] >= min && field->value[n] <= max - && field->value[n] - min < field->maxusage - && field->usage[field->value[n] - min].hid - && search(value, field->value[n], count)) - hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt); - - if (value[n] >= min && value[n] <= max - && value[n] - min < field->maxusage - && field->usage[value[n] - min].hid - && search(field->value, value[n], count)) - hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt); + if (hid_array_value_is_valid(field, field->value[n]) && + search(value, field->value[n], count)) + hid_process_event(hid, + field, + &field->usage[field->value[n] - min], + 0, + interrupt); + + if (hid_array_value_is_valid(field, value[n]) && + search(field->value, value[n], count)) + hid_process_event(hid, + field, + &field->usage[value[n] - min], + 1, + interrupt); } memcpy(field->value, value, count * sizeof(__s32)); -- cgit v1.2.3 From b79c1abae5e19726c5060749e4e7c9e426b045c8 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:17 +0100 Subject: HID: core: split data fetching from processing in hid_input_field() This is a preparatory patch for being able to process the usages out of order. We split the retrieval of the data in a separate function and also split out the processing of the usages depending if the field is an array or a variable. No functional changes from this patch. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-core.c | 96 ++++++++++++++++++++++++++++++++++++++++---------- include/linux/hid.h | 3 +- 2 files changed, 79 insertions(+), 20 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index fad4dbdf6391..34188d7ac0f7 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1544,13 +1544,12 @@ static inline int hid_array_value_is_valid(struct hid_field *field, } /* - * Analyse a received field, and fetch the data from it. The field - * content is stored for next report processing (we do differential - * reporting to the layer). + * Fetch the field from the data. The field content is stored for next + * report processing (we do differential reporting to the layer). */ - -static void hid_input_field(struct hid_device *hid, struct hid_field *field, - __u8 *data, int interrupt) +static void hid_input_fetch_field(struct hid_device *hid, + struct hid_field *field, + __u8 *data) { unsigned n; unsigned count = field->report_count; @@ -1561,6 +1560,7 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, value = field->new_value; memset(value, 0, count * sizeof(__s32)); + field->ignored = false; for (n = 0; n < count; n++) { @@ -1572,21 +1572,56 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, /* Ignore report if ErrorRollOver */ if (!(field->flags & HID_MAIN_ITEM_VARIABLE) && hid_array_value_is_valid(field, value[n]) && - field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) + field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) { + field->ignored = true; return; + } } +} - for (n = 0; n < count; n++) { +/* + * Process a received variable field. + */ - if (HID_MAIN_ITEM_VARIABLE & field->flags) { - hid_process_event(hid, - field, - &field->usage[n], - value[n], - interrupt); - continue; - } +static void hid_input_var_field(struct hid_device *hid, + struct hid_field *field, + int interrupt) +{ + unsigned int count = field->report_count; + __s32 *value = field->new_value; + unsigned int n; + + for (n = 0; n < count; n++) + hid_process_event(hid, + field, + &field->usage[n], + value[n], + interrupt); + + memcpy(field->value, value, count * sizeof(__s32)); +} +/* + * Process a received array field. The field content is stored for + * next report processing (we do differential reporting to the layer). + */ + +static void hid_input_array_field(struct hid_device *hid, + struct hid_field *field, + int interrupt) +{ + unsigned int n; + unsigned int count = field->report_count; + __s32 min = field->logical_minimum; + __s32 *value; + + value = field->new_value; + + /* ErrorRollOver */ + if (field->ignored) + return; + + for (n = 0; n < count; n++) { if (hid_array_value_is_valid(field, field->value[n]) && search(value, field->value[n], count)) hid_process_event(hid, @@ -1607,6 +1642,31 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field, memcpy(field->value, value, count * sizeof(__s32)); } +/* + * Analyse a received report, and fetch the data from it. The field + * content is stored for next report processing (we do differential + * reporting to the layer). + */ +static void hid_process_report(struct hid_device *hid, + struct hid_report *report, + __u8 *data, + int interrupt) +{ + unsigned int a; + struct hid_field *field; + + for (a = 0; a < report->maxfield; a++) { + field = report->field[a]; + + hid_input_fetch_field(hid, field, data); + + if (field->flags & HID_MAIN_ITEM_VARIABLE) + hid_input_var_field(hid, field, interrupt); + else + hid_input_array_field(hid, field, interrupt); + } +} + /* * Output the field into the report. */ @@ -1768,7 +1828,6 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size, struct hid_report_enum *report_enum = hid->report_enum + type; struct hid_report *report; struct hid_driver *hdrv; - unsigned int a; u32 rsize, csize = size; u8 *cdata = data; int ret = 0; @@ -1804,8 +1863,7 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size, } if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) { - for (a = 0; a < report->maxfield; a++) - hid_input_field(hid, report->field[a], cdata, interrupt); + hid_process_report(hid, report, cdata, interrupt); hdrv = hid->driver; if (hdrv && hdrv->report) hdrv->report(hid, report); diff --git a/include/linux/hid.h b/include/linux/hid.h index 3fbfe0986659..cf79eb3da465 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -342,7 +342,7 @@ struct hid_item { * HID device quirks. */ -/* +/* * Increase this if you need to configure more HID quirks at module load time */ #define MAX_USBHID_BOOT_QUIRKS 4 @@ -483,6 +483,7 @@ struct hid_field { __s32 physical_maximum; __s32 unit_exponent; unsigned unit; + bool ignored; /* this field is ignored in this event */ struct hid_report *report; /* associated report */ unsigned index; /* index into report->field[] */ /* hidinput data */ -- cgit v1.2.3 From 3c2b0dbd69901b71848c83d5c642be290198aa13 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:18 +0100 Subject: HID: input: tag touchscreens as such if the physical is not there Some devices (Elan, Synaptics...) are sometimes not setting a physical in their finger collections. hid-input will consider them to be pen devices, leading to some wrong behavior in user space. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-input.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 112901d2d8d2..d2562497a726 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -828,10 +828,31 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel break; case 0x32: /* InRange */ - switch (field->physical & 0xff) { - case 0x21: map_key(BTN_TOOL_MOUSE); break; - case 0x22: map_key(BTN_TOOL_FINGER); break; - default: map_key(BTN_TOOL_PEN); break; + switch (field->physical) { + case HID_DG_PUCK: + map_key(BTN_TOOL_MOUSE); + break; + case HID_DG_FINGER: + map_key(BTN_TOOL_FINGER); + break; + default: + /* + * If the physical is not given, + * rely on the application. + */ + if (!field->physical) { + switch (field->application) { + case HID_DG_TOUCHSCREEN: + case HID_DG_TOUCHPAD: + map_key_clear(BTN_TOOL_FINGER); + break; + default: + map_key_clear(BTN_TOOL_PEN); + } + } else { + map_key(BTN_TOOL_PEN); + } + break; } break; -- cgit v1.2.3 From f2d4ddfa640d2371bad55891159102acd2504108 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:19 +0100 Subject: HID: input: rework spaghetti code with switch statements Instead of using multiple `if (a == b)`, use the switch statement which has been done exactly for that. There should be no functional change (I don't expect moving down HID_QUIRK_{X|Y}_INVERT having any impact. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-input.c | 80 ++++++++++++++++++++++++++----------------------- 1 file changed, 43 insertions(+), 37 deletions(-) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index d2562497a726..54b3e9c5ccc4 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1354,12 +1354,6 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct input = field->hidinput->input; - if (usage->type == EV_ABS && - (((*quirks & HID_QUIRK_X_INVERT) && usage->code == ABS_X) || - ((*quirks & HID_QUIRK_Y_INVERT) && usage->code == ABS_Y))) { - value = field->logical_maximum - value; - } - if (usage->hat_min < usage->hat_max || usage->hat_dir) { int hat_dir = usage->hat_dir; if (!hat_dir) @@ -1370,12 +1364,12 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct return; } - if (usage->hid == HID_DG_INVERT) { + switch (usage->hid) { + case HID_DG_INVERT: *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT); return; - } - if (usage->hid == HID_DG_INRANGE) { + case HID_DG_INRANGE: if (value) { input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1); return; @@ -1383,46 +1377,58 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct input_event(input, usage->type, usage->code, 0); input_event(input, usage->type, BTN_TOOL_RUBBER, 0); return; - } - if (usage->hid == HID_DG_TIPPRESSURE && (*quirks & HID_QUIRK_NOTOUCH)) { - int a = field->logical_minimum; - int b = field->logical_maximum; - input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3)); - } + case HID_DG_TIPPRESSURE: + if (*quirks & HID_QUIRK_NOTOUCH) { + int a = field->logical_minimum; + int b = field->logical_maximum; + + input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3)); + } + break; - if (usage->hid == (HID_UP_PID | 0x83UL)) { /* Simultaneous Effects Max */ + case HID_UP_PID | 0x83UL: /* Simultaneous Effects Max */ dbg_hid("Maximum Effects - %d\n",value); return; - } - if (usage->hid == (HID_UP_PID | 0x7fUL)) { + case HID_UP_PID | 0x7fUL: dbg_hid("PID Pool Report\n"); return; } - if ((usage->type == EV_KEY) && (usage->code == 0)) /* Key 0 is "unassigned", not KEY_UNKNOWN */ - return; + switch (usage->type) { + case EV_KEY: + if (usage->code == 0) /* Key 0 is "unassigned", not KEY_UNKNOWN */ + return; + break; - if ((usage->type == EV_REL) && (usage->code == REL_WHEEL_HI_RES || - usage->code == REL_HWHEEL_HI_RES)) { - hidinput_handle_scroll(usage, input, value); - return; - } + case EV_REL: + if (usage->code == REL_WHEEL_HI_RES || + usage->code == REL_HWHEEL_HI_RES) { + hidinput_handle_scroll(usage, input, value); + return; + } + break; - if ((usage->type == EV_ABS) && (field->flags & HID_MAIN_ITEM_RELATIVE) && - (usage->code == ABS_VOLUME)) { - int count = abs(value); - int direction = value > 0 ? KEY_VOLUMEUP : KEY_VOLUMEDOWN; - int i; + case EV_ABS: + if ((field->flags & HID_MAIN_ITEM_RELATIVE) && + usage->code == ABS_VOLUME) { + int count = abs(value); + int direction = value > 0 ? KEY_VOLUMEUP : KEY_VOLUMEDOWN; + int i; + + for (i = 0; i < count; i++) { + input_event(input, EV_KEY, direction, 1); + input_sync(input); + input_event(input, EV_KEY, direction, 0); + input_sync(input); + } + return; - for (i = 0; i < count; i++) { - input_event(input, EV_KEY, direction, 1); - input_sync(input); - input_event(input, EV_KEY, direction, 0); - input_sync(input); - } - return; + } else if (((*quirks & HID_QUIRK_X_INVERT) && usage->code == ABS_X) || + ((*quirks & HID_QUIRK_Y_INVERT) && usage->code == ABS_Y)) + value = field->logical_maximum - value; + break; } /* -- cgit v1.2.3 From 187ccd6caa4b40dcfbcb2531746e9fe500414e79 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:20 +0100 Subject: HID: input: move up out-of-range processing of input values It actually makes sense to clamp the value to its boundaries before doing further processing. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-input.c | 48 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 54b3e9c5ccc4..8770d9a2b2af 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -1364,6 +1364,30 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct return; } + /* + * Ignore out-of-range values as per HID specification, + * section 5.10 and 6.2.25, when NULL state bit is present. + * When it's not, clamp the value to match Microsoft's input + * driver as mentioned in "Required HID usages for digitizers": + * https://msdn.microsoft.com/en-us/library/windows/hardware/dn672278(v=vs.85).asp + * + * The logical_minimum < logical_maximum check is done so that we + * don't unintentionally discard values sent by devices which + * don't specify logical min and max. + */ + if ((field->flags & HID_MAIN_ITEM_VARIABLE) && + field->logical_minimum < field->logical_maximum) { + if (field->flags & HID_MAIN_ITEM_NULL_STATE && + (value < field->logical_minimum || + value > field->logical_maximum)) { + dbg_hid("Ignoring out-of-range value %x\n", value); + return; + } + value = clamp(value, + field->logical_minimum, + field->logical_maximum); + } + switch (usage->hid) { case HID_DG_INVERT: *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT); @@ -1431,30 +1455,6 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct break; } - /* - * Ignore out-of-range values as per HID specification, - * section 5.10 and 6.2.25, when NULL state bit is present. - * When it's not, clamp the value to match Microsoft's input - * driver as mentioned in "Required HID usages for digitizers": - * https://msdn.microsoft.com/en-us/library/windows/hardware/dn672278(v=vs.85).asp - * - * The logical_minimum < logical_maximum check is done so that we - * don't unintentionally discard values sent by devices which - * don't specify logical min and max. - */ - if ((field->flags & HID_MAIN_ITEM_VARIABLE) && - (field->logical_minimum < field->logical_maximum)) { - if (field->flags & HID_MAIN_ITEM_NULL_STATE && - (value < field->logical_minimum || - value > field->logical_maximum)) { - dbg_hid("Ignoring out-of-range value %x\n", value); - return; - } - value = clamp(value, - field->logical_minimum, - field->logical_maximum); - } - /* * Ignore reports for absolute data if the data didn't change. This is * not only an optimization but also fixes 'dead' key reports. Some -- cgit v1.2.3 From 22f4b026c3ddd4b26c5baa202bd3ee38feaa2e9a Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:21 +0100 Subject: HID: compute an ordered list of input fields to process This will be used in a later commit: we build a list of input fields (and usage_index) that is ordered based on a usage priority. Changing the usage priority allows to re-order the processed list, meaning that we can enforce some usages to be process before others. For instance, before processing InRange in the HID tablets, we need to know if we are using the eraser (side or button). Enforcing a higher (lower number) priority for Invert allows to force the input stack to process that field before. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-core.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++++- include/linux/hid.h | 10 +++++ 2 files changed, 114 insertions(+), 1 deletion(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 34188d7ac0f7..b38528118642 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -81,6 +81,7 @@ struct hid_report *hid_register_report(struct hid_device *device, report_enum->report_id_hash[id] = report; list_add_tail(&report->list, &report_enum->report_list); + INIT_LIST_HEAD(&report->field_entry_list); return report; } @@ -101,7 +102,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned field = kzalloc((sizeof(struct hid_field) + usages * sizeof(struct hid_usage) + - 2 * usages * sizeof(unsigned int)), GFP_KERNEL); + 3 * usages * sizeof(unsigned int)), GFP_KERNEL); if (!field) return NULL; @@ -110,6 +111,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned field->usage = (struct hid_usage *)(field + 1); field->value = (s32 *)(field->usage + usages); field->new_value = (s32 *)(field->value + usages); + field->usages_priorities = (s32 *)(field->new_value + usages); field->report = report; return field; @@ -657,6 +659,8 @@ static void hid_free_report(struct hid_report *report) { unsigned n; + kfree(report->field_entries); + for (n = 0; n < report->maxfield; n++) kfree(report->field[n]); kfree(report); @@ -1667,6 +1671,103 @@ static void hid_process_report(struct hid_device *hid, } } +/* + * Insert a given usage_index in a field in the list + * of processed usages in the report. + * + * The elements of lower priority score are processed + * first. + */ +static void __hid_insert_field_entry(struct hid_device *hid, + struct hid_report *report, + struct hid_field_entry *entry, + struct hid_field *field, + unsigned int usage_index) +{ + struct hid_field_entry *next; + + entry->field = field; + entry->index = usage_index; + entry->priority = field->usages_priorities[usage_index]; + + /* insert the element at the correct position */ + list_for_each_entry(next, + &report->field_entry_list, + list) { + /* + * the priority of our element is strictly higher + * than the next one, insert it before + */ + if (entry->priority > next->priority) { + list_add_tail(&entry->list, &next->list); + return; + } + } + + /* lowest priority score: insert at the end */ + list_add_tail(&entry->list, &report->field_entry_list); +} + +static void hid_report_process_ordering(struct hid_device *hid, + struct hid_report *report) +{ + struct hid_field *field; + struct hid_field_entry *entries; + unsigned int a, u, usages; + unsigned int count = 0; + + /* count the number of individual fields in the report */ + for (a = 0; a < report->maxfield; a++) { + field = report->field[a]; + + if (field->flags & HID_MAIN_ITEM_VARIABLE) + count += field->report_count; + else + count++; + } + + /* allocate the memory to process the fields */ + entries = kcalloc(count, sizeof(*entries), GFP_KERNEL); + if (!entries) + return; + + report->field_entries = entries; + + /* + * walk through all fields in the report and + * store them by priority order in report->field_entry_list + * + * - Var elements are individualized (field + usage_index) + * - Arrays are taken as one, we can not chose an order for them + */ + usages = 0; + for (a = 0; a < report->maxfield; a++) { + field = report->field[a]; + + if (field->flags & HID_MAIN_ITEM_VARIABLE) { + for (u = 0; u < field->report_count; u++) { + __hid_insert_field_entry(hid, report, + &entries[usages], + field, u); + usages++; + } + } else { + __hid_insert_field_entry(hid, report, &entries[usages], + field, 0); + usages++; + } + } +} + +static void hid_process_ordering(struct hid_device *hid) +{ + struct hid_report *report; + struct hid_report_enum *report_enum = &hid->report_enum[HID_INPUT_REPORT]; + + list_for_each_entry(report, &report_enum->report_list, list) + hid_report_process_ordering(hid, report); +} + /* * Output the field into the report. */ @@ -2050,6 +2151,8 @@ int hid_connect(struct hid_device *hdev, unsigned int connect_mask) return -ENODEV; } + hid_process_ordering(hdev); + if ((hdev->claimed & HID_CLAIMED_INPUT) && (connect_mask & HID_CONNECT_FF) && hdev->ff_init) hdev->ff_init(hdev); diff --git a/include/linux/hid.h b/include/linux/hid.h index cf79eb3da465..f25020c0d6b8 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -477,6 +477,7 @@ struct hid_field { unsigned report_type; /* (input,output,feature) */ __s32 *value; /* last known value(s) */ __s32 *new_value; /* newly read value(s) */ + __s32 *usages_priorities; /* priority of each usage when reading the report */ __s32 logical_minimum; __s32 logical_maximum; __s32 physical_minimum; @@ -493,13 +494,22 @@ struct hid_field { #define HID_MAX_FIELDS 256 +struct hid_field_entry { + struct list_head list; + struct hid_field *field; + unsigned int index; + __s32 priority; +}; + struct hid_report { struct list_head list; struct list_head hidinput_list; + struct list_head field_entry_list; /* ordered list of input fields */ unsigned int id; /* id of this report */ unsigned int type; /* report type */ unsigned int application; /* application usage for this report */ struct hid_field *field[HID_MAX_FIELDS]; /* fields of the report */ + struct hid_field_entry *field_entries; /* allocated memory of input field_entry */ unsigned maxfield; /* maximum valid field index */ unsigned size; /* size of the report (bits) */ struct hid_device *device; /* associated device */ -- cgit v1.2.3 From bebcc522fbee4bf51a2571378154ef2a4bf14724 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:22 +0100 Subject: HID: core: for input reports, process the usages by priority list Now that we have a list of fields/usages by priority order, walk through that list to process the inputs instead of using the order provided by the manufacturer. Note that this changes the way we update the values in the struct hid_field: Previously, once a field was processed, we updated the new values. Now we need to wait for the entire report to be processed to update the values. I don't think it will be an issue: because we were relying on the device ordering, there were no guarantees to have a field stored before an other. Which is why we introduced .report() in drivers to have those values updated. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-core.c | 45 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 38 insertions(+), 7 deletions(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index b38528118642..db925794fbe6 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1657,17 +1657,48 @@ static void hid_process_report(struct hid_device *hid, int interrupt) { unsigned int a; + struct hid_field_entry *entry; struct hid_field *field; - for (a = 0; a < report->maxfield; a++) { - field = report->field[a]; + /* first retrieve all incoming values in data */ + for (a = 0; a < report->maxfield; a++) + hid_input_fetch_field(hid, field = report->field[a], data); + + if (!list_empty(&report->field_entry_list)) { + /* INPUT_REPORT, we have a priority list of fields */ + list_for_each_entry(entry, + &report->field_entry_list, + list) { + field = entry->field; + + if (field->flags & HID_MAIN_ITEM_VARIABLE) + hid_process_event(hid, + field, + &field->usage[entry->index], + field->new_value[entry->index], + interrupt); + else + hid_input_array_field(hid, field, interrupt); + } - hid_input_fetch_field(hid, field, data); + /* we need to do the memcpy at the end for var items */ + for (a = 0; a < report->maxfield; a++) { + field = report->field[a]; - if (field->flags & HID_MAIN_ITEM_VARIABLE) - hid_input_var_field(hid, field, interrupt); - else - hid_input_array_field(hid, field, interrupt); + if (field->flags & HID_MAIN_ITEM_VARIABLE) + memcpy(field->value, field->new_value, + field->report_count * sizeof(__s32)); + } + } else { + /* FEATURE_REPORT, regular processing */ + for (a = 0; a < report->maxfield; a++) { + field = report->field[a]; + + if (field->flags & HID_MAIN_ITEM_VARIABLE) + hid_input_var_field(hid, field, interrupt); + else + hid_input_array_field(hid, field, interrupt); + } } } -- cgit v1.2.3 From 048cddfd440583a07530774fe20c7d26d7378155 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:23 +0100 Subject: HID: input: enforce Invert usage to be processed before InRange When a device exposes both Invert and InRange, Invert must be processed before InRange. If we keep the order of the device and we process them out of order, InRange will first set BTN_TOOL_PEN, and then Invert will set BTN_TOOL_RUBBER. Userspace knows how to deal with that situation, but fixing it in the kernel is now easier. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-input.c | 34 ++++++++++++++++++++++++++++++++-- include/linux/hid.h | 4 +++- 2 files changed, 35 insertions(+), 3 deletions(-) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 8770d9a2b2af..61d91117f4ae 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -48,6 +48,25 @@ static const struct { __s32 y; } hid_hat_to_axis[] = {{ 0, 0}, { 0,-1}, { 1,-1}, { 1, 0}, { 1, 1}, { 0, 1}, {-1, 1}, {-1, 0}, {-1,-1}}; +/* + * hid-input will convert this list into priorities: + * the first element will have the highest priority + * (the length of the following array) and the last + * element the lowest (1). + * + * hid-input will then shift the priority by 8 bits to leave some space + * in case drivers want to interleave other fields. + * + * If drivers want to add fields before those, hid-input will + * leave out the first 8 bits of the priority value. + * + * This still leaves us 65535 individual priority values. + */ +static const __u32 hidinput_usages_priorities[] = { + HID_DG_INVERT, /* Invert must always come before In Range */ + HID_DG_INRANGE, +}; + #define map_abs(c) hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c)) #define map_rel(c) hid_map_usage(hidinput, usage, &bit, &max, EV_REL, (c)) #define map_key(c) hid_map_usage(hidinput, usage, &bit, &max, EV_KEY, (c)) @@ -586,11 +605,12 @@ static bool hidinput_field_in_collection(struct hid_device *device, struct hid_f } static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_field *field, - struct hid_usage *usage) + struct hid_usage *usage, unsigned int usage_index) { struct input_dev *input = hidinput->input; struct hid_device *device = input_get_drvdata(input); int max = 0, code; + unsigned int i = 0; unsigned long *bit = NULL; field->hidinput = hidinput; @@ -608,6 +628,15 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel goto ignore; } + /* assign a priority based on the static list declared here */ + for (i = 0; i < ARRAY_SIZE(hidinput_usages_priorities); i++) { + if (usage->hid == hidinput_usages_priorities[i]) { + field->usages_priorities[usage_index] = + (ARRAY_SIZE(hidinput_usages_priorities) - i) << 8; + break; + } + } + if (device->driver->input_mapping) { int ret = device->driver->input_mapping(device, hidinput, field, usage, &bit, &max); @@ -1962,7 +1991,8 @@ static inline void hidinput_configure_usages(struct hid_input *hidinput, for (i = 0; i < report->maxfield; i++) for (j = 0; j < report->field[i]->maxusage; j++) hidinput_configure_usage(hidinput, report->field[i], - report->field[i]->usage + j); + report->field[i]->usage + j, + j); } /* diff --git a/include/linux/hid.h b/include/linux/hid.h index f25020c0d6b8..eaad0655b05c 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -477,7 +477,9 @@ struct hid_field { unsigned report_type; /* (input,output,feature) */ __s32 *value; /* last known value(s) */ __s32 *new_value; /* newly read value(s) */ - __s32 *usages_priorities; /* priority of each usage when reading the report */ + __s32 *usages_priorities; /* priority of each usage when reading the report + * bits 8-16 are reserved for hid-input usage + */ __s32 logical_minimum; __s32 logical_maximum; __s32 physical_minimum; -- cgit v1.2.3 From 87562fcd134214a68e58d0714b820f2f2da75b1f Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:24 +0100 Subject: HID: input: remove the need for HID_QUIRK_INVERT HID_QUIRK_INVERT is kind of complex to deal with and was bogus. Furthermore, it didn't make sense to use a global per struct hid_device quirk for something dynamic as the current state. Store the current tool information in the report itself, and re-order the processing of the fields to enforce having all the tablet "state" fields before getting to In Range and other input fields. This way, we now have all the information whether a tool is present or not while processing In Range. This new behavior enforces that only one tool gets forwarded to userspace at the same time, and that if either eraser or invert is set, we enforce BTN_TOOL_RUBBER. Note that the release of the previous tool now happens in its own EV_SYN report so userspace doesn't get confused by having 2 tools. These changes are tested in the following hid-tools regression tests: https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127 Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-input.c | 98 +++++++++++++++++++++++++++++++++++++++++++++---- include/linux/hid.h | 6 ++- 2 files changed, 95 insertions(+), 9 deletions(-) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 61d91117f4ae..9f8853640648 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -63,8 +63,11 @@ static const struct { * This still leaves us 65535 individual priority values. */ static const __u32 hidinput_usages_priorities[] = { + HID_DG_ERASER, /* Eraser (eraser touching) must always come before tipswitch */ HID_DG_INVERT, /* Invert must always come before In Range */ - HID_DG_INRANGE, + HID_DG_TIPSWITCH, /* Is the tip of the tool touching? */ + HID_DG_TIPPRESSURE, /* Tip Pressure might emulate tip switch */ + HID_DG_INRANGE, /* In Range needs to come after the other tool states */ }; #define map_abs(c) hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c)) @@ -1365,9 +1368,38 @@ static void hidinput_handle_scroll(struct hid_usage *usage, input_event(input, EV_REL, usage->code, hi_res); } +static void hid_report_release_tool(struct hid_report *report, struct input_dev *input, + unsigned int tool) +{ + /* if the given tool is not currently reported, ignore */ + if (!test_bit(tool, input->key)) + return; + + /* + * if the given tool was previously set, release it, + * release any TOUCH and send an EV_SYN + */ + input_event(input, EV_KEY, BTN_TOUCH, 0); + input_event(input, EV_KEY, tool, 0); + input_event(input, EV_SYN, SYN_REPORT, 0); + + report->tool = 0; +} + +static void hid_report_set_tool(struct hid_report *report, struct input_dev *input, + unsigned int new_tool) +{ + if (report->tool != new_tool) + hid_report_release_tool(report, input, report->tool); + + input_event(input, EV_KEY, new_tool, 1); + report->tool = new_tool; +} + void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct hid_usage *usage, __s32 value) { struct input_dev *input; + struct hid_report *report = field->report; unsigned *quirks = &hid->quirks; if (!usage->type) @@ -1418,25 +1450,75 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct } switch (usage->hid) { + case HID_DG_ERASER: + report->tool_active |= !!value; + + /* + * if eraser is set, we must enforce BTN_TOOL_RUBBER + * to accommodate for devices not following the spec. + */ + if (value) + hid_report_set_tool(report, input, BTN_TOOL_RUBBER); + else if (report->tool != BTN_TOOL_RUBBER) + /* value is off, tool is not rubber, ignore */ + return; + + /* let hid-input set BTN_TOUCH */ + break; + case HID_DG_INVERT: - *quirks = value ? (*quirks | HID_QUIRK_INVERT) : (*quirks & ~HID_QUIRK_INVERT); + report->tool_active |= !!value; + + /* + * If invert is set, we store BTN_TOOL_RUBBER. + */ + if (value) + hid_report_set_tool(report, input, BTN_TOOL_RUBBER); + else if (!report->tool_active) + /* tool_active not set means Invert and Eraser are not set */ + hid_report_release_tool(report, input, BTN_TOOL_RUBBER); + + /* no further processing */ return; case HID_DG_INRANGE: - if (value) { - input_event(input, usage->type, (*quirks & HID_QUIRK_INVERT) ? BTN_TOOL_RUBBER : usage->code, 1); - return; + report->tool_active |= !!value; + + if (report->tool_active) { + /* + * if tool is not set but is marked as active, + * assume ours + */ + if (!report->tool) + hid_report_set_tool(report, input, usage->code); + } else { + hid_report_release_tool(report, input, usage->code); } - input_event(input, usage->type, usage->code, 0); - input_event(input, usage->type, BTN_TOOL_RUBBER, 0); + + /* reset tool_active for the next event */ + report->tool_active = false; + + /* no further processing */ return; + case HID_DG_TIPSWITCH: + report->tool_active |= !!value; + + /* if tool is set to RUBBER we should ignore the current value */ + if (report->tool == BTN_TOOL_RUBBER) + return; + + break; + case HID_DG_TIPPRESSURE: if (*quirks & HID_QUIRK_NOTOUCH) { int a = field->logical_minimum; int b = field->logical_maximum; - input_event(input, EV_KEY, BTN_TOUCH, value > a + ((b - a) >> 3)); + if (value > a + ((b - a) >> 3)) { + input_event(input, EV_KEY, BTN_TOUCH, 1); + report->tool_active = true; + } } break; diff --git a/include/linux/hid.h b/include/linux/hid.h index eaad0655b05c..feb8df61168f 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -347,7 +347,7 @@ struct hid_item { */ #define MAX_USBHID_BOOT_QUIRKS 4 -#define HID_QUIRK_INVERT BIT(0) +/* BIT(0) reserved for backward compatibility, was HID_QUIRK_INVERT */ #define HID_QUIRK_NOTOUCH BIT(1) #define HID_QUIRK_IGNORE BIT(2) #define HID_QUIRK_NOGET BIT(3) @@ -515,6 +515,10 @@ struct hid_report { unsigned maxfield; /* maximum valid field index */ unsigned size; /* size of the report (bits) */ struct hid_device *device; /* associated device */ + + /* tool related state */ + bool tool_active; /* whether the current tool is active */ + unsigned int tool; /* BTN_TOOL_* */ }; #define HID_MAX_IDS 256 -- cgit v1.2.3 From 5c20000a4756f57c824e3045c978ef19136a676d Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:25 +0100 Subject: HID: input: accommodate priorities for slotted devices Multitouch devices in hybrid mode are reporting multiple times the same collection. We should accommodate for this in our handling of priorities by defining the slots they belong to. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- drivers/hid/hid-input.c | 103 ++++++++++++++++++++++++++++++++++++++++++++---- include/linux/hid.h | 1 + 2 files changed, 96 insertions(+), 8 deletions(-) diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 9f8853640648..56d4e91c4750 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -48,6 +48,16 @@ static const struct { __s32 y; } hid_hat_to_axis[] = {{ 0, 0}, { 0,-1}, { 1,-1}, { 1, 0}, { 1, 1}, { 0, 1}, {-1, 1}, {-1, 0}, {-1,-1}}; +struct usage_priority { + __u32 usage; /* the HID usage associated */ + bool global; /* we assume all usages to be slotted, + * unless global + */ + unsigned int slot_overwrite; /* for globals: allows to set the usage + * before or after the slots + */ +}; + /* * hid-input will convert this list into priorities: * the first element will have the highest priority @@ -57,17 +67,30 @@ static const struct { * hid-input will then shift the priority by 8 bits to leave some space * in case drivers want to interleave other fields. * + * To accommodate slotted devices, the slot priority is + * defined in the next 8 bits (defined by 0xff - slot). + * * If drivers want to add fields before those, hid-input will * leave out the first 8 bits of the priority value. * * This still leaves us 65535 individual priority values. */ -static const __u32 hidinput_usages_priorities[] = { - HID_DG_ERASER, /* Eraser (eraser touching) must always come before tipswitch */ - HID_DG_INVERT, /* Invert must always come before In Range */ - HID_DG_TIPSWITCH, /* Is the tip of the tool touching? */ - HID_DG_TIPPRESSURE, /* Tip Pressure might emulate tip switch */ - HID_DG_INRANGE, /* In Range needs to come after the other tool states */ +static const struct usage_priority hidinput_usages_priorities[] = { + { /* Eraser (eraser touching) must always come before tipswitch */ + .usage = HID_DG_ERASER, + }, + { /* Invert must always come before In Range */ + .usage = HID_DG_INVERT, + }, + { /* Is the tip of the tool touching? */ + .usage = HID_DG_TIPSWITCH, + }, + { /* Tip Pressure might emulate tip switch */ + .usage = HID_DG_TIPPRESSURE, + }, + { /* In Range needs to come after the other tool states */ + .usage = HID_DG_INRANGE, + }, }; #define map_abs(c) hid_map_usage(hidinput, usage, &bit, &max, EV_ABS, (c)) @@ -612,6 +635,7 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel { struct input_dev *input = hidinput->input; struct hid_device *device = input_get_drvdata(input); + const struct usage_priority *usage_priority = NULL; int max = 0, code; unsigned int i = 0; unsigned long *bit = NULL; @@ -633,13 +657,26 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel /* assign a priority based on the static list declared here */ for (i = 0; i < ARRAY_SIZE(hidinput_usages_priorities); i++) { - if (usage->hid == hidinput_usages_priorities[i]) { + if (usage->hid == hidinput_usages_priorities[i].usage) { + usage_priority = &hidinput_usages_priorities[i]; + field->usages_priorities[usage_index] = (ARRAY_SIZE(hidinput_usages_priorities) - i) << 8; break; } } + /* + * For slotted devices, we need to also add the slot index + * in the priority. + */ + if (usage_priority && usage_priority->global) + field->usages_priorities[usage_index] |= + usage_priority->slot_overwrite; + else + field->usages_priorities[usage_index] |= + (0xff - field->slot_idx) << 16; + if (device->driver->input_mapping) { int ret = device->driver->input_mapping(device, hidinput, field, usage, &bit, &max); @@ -2068,7 +2105,57 @@ static struct hid_input *hidinput_match_application(struct hid_report *report) static inline void hidinput_configure_usages(struct hid_input *hidinput, struct hid_report *report) { - int i, j; + int i, j, k; + int first_field_index = 0; + int slot_collection_index = -1; + int prev_collection_index = -1; + unsigned int slot_idx = 0; + struct hid_field *field; + + /* + * First tag all the fields that are part of a slot, + * a slot needs to have one Contact ID in the collection + */ + for (i = 0; i < report->maxfield; i++) { + field = report->field[i]; + + /* ignore fields without usage */ + if (field->maxusage < 1) + continue; + + /* + * janitoring when collection_index changes + */ + if (prev_collection_index != field->usage->collection_index) { + prev_collection_index = field->usage->collection_index; + first_field_index = i; + } + + /* + * if we already found a Contact ID in the collection, + * tag and continue to the next. + */ + if (slot_collection_index == field->usage->collection_index) { + field->slot_idx = slot_idx; + continue; + } + + /* check if the current field has Contact ID */ + for (j = 0; j < field->maxusage; j++) { + if (field->usage[j].hid == HID_DG_CONTACTID) { + slot_collection_index = field->usage->collection_index; + slot_idx++; + + /* + * mark all previous fields and this one in the + * current collection to be slotted. + */ + for (k = first_field_index; k <= i; k++) + report->field[k]->slot_idx = slot_idx; + break; + } + } + } for (i = 0; i < report->maxfield; i++) for (j = 0; j < report->field[i]->maxusage; j++) diff --git a/include/linux/hid.h b/include/linux/hid.h index feb8df61168f..4363a63b9775 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -492,6 +492,7 @@ struct hid_field { /* hidinput data */ struct hid_input *hidinput; /* associated input structure */ __u16 dpad; /* dpad input code */ + unsigned int slot_idx; /* slot index in a report */ }; #define HID_MAX_FIELDS 256 -- cgit v1.2.3 From 42764f97e6ebf1ff518c83e4a36395fddf7a6085 Mon Sep 17 00:00:00 2001 From: Benjamin Tissoires Date: Thu, 3 Feb 2022 15:32:26 +0100 Subject: Input: docs: add more details on the use of BTN_TOOL The HID core stack used to be very relaxed considering the BTN_TOOL_* usage. With the recent commits, we should now enforce to have only one tool at a time, meaning that we can now express that requirement in the docs. Signed-off-by: Benjamin Tissoires Reviewed-by: Ping Cheng Acked-by: Peter Hutterer Signed-off-by: Jiri Kosina --- Documentation/input/event-codes.rst | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/Documentation/input/event-codes.rst b/Documentation/input/event-codes.rst index b24ae7d292cc..8741d390b184 100644 --- a/Documentation/input/event-codes.rst +++ b/Documentation/input/event-codes.rst @@ -137,7 +137,11 @@ A few EV_KEY codes have special meanings: code should be set to a value of 1. When the tool is no longer interacting with the input device, the BTN_TOOL_ code should be reset to 0. All trackpads, tablets, and touchscreens should use at least one BTN_TOOL_ - code when events are generated. + code when events are generated. Likewise all trackpads, tablets, and + touchscreens should export only one BTN_TOOL_ at a time. To not break + existing userspace, it is recommended to not switch tool in one EV_SYN frame + but first emitting the old BTN_TOOL_ at 0, then emit one SYN_REPORT + and then set the new BTN_TOOL_ at 1. * BTN_TOUCH: -- cgit v1.2.3