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* [PATCH v2 00/12] HID: fix for generic input processing
@ 2022-02-03 14:32 Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 01/12] HID: core: statically allocate read buffers Benjamin Tissoires
                   ` (12 more replies)
  0 siblings, 13 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

Hi,

this is the v2 of my series which reworks the HID report processing.

I took Ping's comments into account, and amended my MR with the
regression tests[0].
More specifically, the tests (and thus this new version of the series)
enforces that only one BTN_TOOL_* event gets forwarded between each
EV_SYN frame, and that BTN_TOUCH are properly translated too.

This also magivally solved some worrying transitions we had in the
pen state machine where the pen was jumping from "eraser" to "in
contact". This new behavior enforces a "out-of-range" state in the
middle, making it easier for userspace to understand now.

Again, tests are welcome :)

Cheers,
Benjamin

[0] https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127

Benjamin Tissoires (12):
  HID: core: statically allocate read buffers
  HID: core: de-duplicate some code in hid_input_field()
  HID: core: split data fetching from processing in hid_input_field()
  HID: input: tag touchscreens as such if the physical is not there
  HID: input: rework spaghetti code with switch statements
  HID: input: move up out-of-range processing of input values
  HID: compute an ordered list of input fields to process
  HID: core: for input reports, process the usages by priority list
  HID: input: enforce Invert usage to be processed before InRange
  HID: input: remove the need for HID_QUIRK_INVERT
  HID: input: accommodate priorities for slotted devices
  Input: docs: add more details on the use of BTN_TOOL

 Documentation/input/event-codes.rst |   6 +-
 drivers/hid/hid-core.c              | 280 ++++++++++++++++++---
 drivers/hid/hid-input.c             | 364 ++++++++++++++++++++++------
 include/linux/hid.h                 |  23 +-
 4 files changed, 568 insertions(+), 105 deletions(-)

-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 01/12] HID: core: statically allocate read buffers
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 02/12] HID: core: de-duplicate some code in hid_input_field() Benjamin Tissoires
                   ` (11 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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;
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 02/12] HID: core: de-duplicate some code in hid_input_field()
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 01/12] HID: core: statically allocate read buffers Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 03/12] HID: core: split data fetching from processing " Benjamin Tissoires
                   ` (10 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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));
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 03/12] HID: core: split data fetching from processing in hid_input_field()
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 01/12] HID: core: statically allocate read buffers Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 02/12] HID: core: de-duplicate some code in hid_input_field() Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 04/12] HID: input: tag touchscreens as such if the physical is not there Benjamin Tissoires
                   ` (9 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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 */
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 04/12] HID: input: tag touchscreens as such if the physical is not there
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (2 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 03/12] HID: core: split data fetching from processing " Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 05/12] HID: input: rework spaghetti code with switch statements Benjamin Tissoires
                   ` (8 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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;
 
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 05/12] HID: input: rework spaghetti code with switch statements
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (3 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 04/12] HID: input: tag touchscreens as such if the physical is not there Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 06/12] HID: input: move up out-of-range processing of input values Benjamin Tissoires
                   ` (7 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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;
 	}
 
 	/*
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 06/12] HID: input: move up out-of-range processing of input values
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (4 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 05/12] HID: input: rework spaghetti code with switch statements Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 07/12] HID: compute an ordered list of input fields to process Benjamin Tissoires
                   ` (6 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

It actually makes sense to clamp the value to its boundaries before
doing further processing.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 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
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 07/12] HID: compute an ordered list of input fields to process
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (5 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 06/12] HID: input: move up out-of-range processing of input values Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 08/12] HID: core: for input reports, process the usages by priority list Benjamin Tissoires
                   ` (5 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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 */
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 08/12] HID: core: for input reports, process the usages by priority list
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (6 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 07/12] HID: compute an ordered list of input fields to process Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 09/12] HID: input: enforce Invert usage to be processed before InRange Benjamin Tissoires
                   ` (4 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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);
+		}
 	}
 }
 
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 09/12] HID: input: enforce Invert usage to be processed before InRange
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (7 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 08/12] HID: core: for input reports, process the usages by priority list Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT Benjamin Tissoires
                   ` (3 subsequent siblings)
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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;
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (8 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 09/12] HID: input: enforce Invert usage to be processed before InRange Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-04  1:41   ` Ping Cheng
  2022-02-10  5:21   ` Ping Cheng
  2022-02-03 14:32 ` [PATCH v2 11/12] HID: input: accommodate priorities for slotted devices Benjamin Tissoires
                   ` (2 subsequent siblings)
  12 siblings, 2 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>

---

Changes in v2:
- rework the entire tool switching, this makes the processing
  slightly more complex but is better for existing userspace.
---
 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
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 11/12] HID: input: accommodate priorities for slotted devices
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (9 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-03 14:32 ` [PATCH v2 12/12] Input: docs: add more details on the use of BTN_TOOL Benjamin Tissoires
  2022-03-01 14:53 ` [PATCH v2 00/12] HID: fix for generic input processing Jiri Kosina
  12 siblings, 0 replies; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>
---
 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
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* [PATCH v2 12/12] Input: docs: add more details on the use of BTN_TOOL
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (10 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 11/12] HID: input: accommodate priorities for slotted devices Benjamin Tissoires
@ 2022-02-03 14:32 ` Benjamin Tissoires
  2022-02-16  5:40   ` Peter Hutterer
  2022-03-01 14:53 ` [PATCH v2 00/12] HID: fix for generic input processing Jiri Kosina
  12 siblings, 1 reply; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-03 14:32 UTC (permalink / raw)
  To: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, Peter Hutterer
  Cc: linux-input, linux-doc, linux-kernel, Benjamin Tissoires

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 <benjamin.tissoires@redhat.com>

---

changes in v2:
- changed to explain that switching tool in one EV_SYN report
  is not nice for userspace
---
 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_<name> code should be reset to 0. All
     trackpads, tablets, and touchscreens should use at least one BTN_TOOL_<name>
-    code when events are generated.
+    code when events are generated. Likewise all trackpads, tablets, and
+    touchscreens should export only one BTN_TOOL_<name> 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_<name> at 0, then emit one SYN_REPORT
+    and then set the new BTN_TOOL_<name> at 1.
 
 * BTN_TOUCH:
 
-- 
2.33.1


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-03 14:32 ` [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT Benjamin Tissoires
@ 2022-02-04  1:41   ` Ping Cheng
  2022-02-10  5:21   ` Ping Cheng
  1 sibling, 0 replies; 23+ messages in thread
From: Ping Cheng @ 2022-02-04  1:41 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, linux-input, linux-doc, linux-kernel

Hi Benjamin,

The logic looks good to me. The whole set is:

Reviewed-by: Ping Cheng <ping.cheng@wacom.com>

You may want to wait for a few days to give felixbecker2
(https://github.com/linuxwacom/xf86-input-wacom/issues/186) an
opportunity to test the patchset.

Thank you for your excellent work!
Ping

On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> 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 <benjamin.tissoires@redhat.com>
>
> ---
>
> Changes in v2:
> - rework the entire tool switching, this makes the processing
>   slightly more complex but is better for existing userspace.
> ---
>  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
> --
> 2.33.1
>

^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-03 14:32 ` [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT Benjamin Tissoires
  2022-02-04  1:41   ` Ping Cheng
@ 2022-02-10  5:21   ` Ping Cheng
  2022-02-10  5:43     ` Ping Cheng
  1 sibling, 1 reply; 23+ messages in thread
From: Ping Cheng @ 2022-02-10  5:21 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, linux-input, linux-doc, linux-kernel

On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> 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 <benjamin.tissoires@redhat.com>
>
> ---
>
> Changes in v2:
> - rework the entire tool switching, this makes the processing
>   slightly more complex but is better for existing userspace.
> ---
>  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);

Took a while for me to find the right device and setup the proper
system for the testing. This block missing the serial number:

input_event(input, EV_MSC, MSC_SERIAL, 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
> --
> 2.33.1
>

^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-10  5:21   ` Ping Cheng
@ 2022-02-10  5:43     ` Ping Cheng
  2022-02-14 10:23       ` Benjamin Tissoires
  0 siblings, 1 reply; 23+ messages in thread
From: Ping Cheng @ 2022-02-10  5:43 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, linux-input, linux-doc, linux-kernel

Sorry for the noise. Hit the wrong buttons...

On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
>
> On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
> >
> > 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 <benjamin.tissoires@redhat.com>
> >
> > ---
> >
> > Changes in v2:
> > - rework the entire tool switching, this makes the processing
> >   slightly more complex but is better for existing userspace.
> > ---
> >  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);

Took a while for me to find the right device and setup the proper
system for the testing. This block missing the serial number:

        input_event(input, EV_MSC, MSC_SERIAL, 0);

Without this line, the next tool will not get its serial number.

> > +       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;

This case should return before HID_DG_INVERT is checked since we may
get TIPSWITCH bit before INVERT. In fact, the device that I tested
sends the tipswatch bit before the invert bit. So, I alway get a PEN
in and out before I get ERASER events, when I bring the pen in with
the side-switch/invert bit pressed.

However, we know not all devices support INVERT. We probably have to
keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
wait until HID_DG_INVERT is reached.

If you are interested in the evtest output, please let me know. I'll
share it with you offline so we don't abuse this list...

Cheers,
Ping

> > +               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
> > --
> > 2.33.1
> >

^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-10  5:43     ` Ping Cheng
@ 2022-02-14 10:23       ` Benjamin Tissoires
  2022-02-15  2:04         ` Ping Cheng
  0 siblings, 1 reply; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-14 10:23 UTC (permalink / raw)
  To: Ping Cheng
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, open list:HID CORE LAYER, Linux Doc Mailing List,
	lkml

Hi Ping,

On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
>
> Sorry for the noise. Hit the wrong buttons...
>
> On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> >
> > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > <benjamin.tissoires@redhat.com> wrote:
> > >
> > > 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 <benjamin.tissoires@redhat.com>
> > >
> > > ---
> > >
> > > Changes in v2:
> > > - rework the entire tool switching, this makes the processing
> > >   slightly more complex but is better for existing userspace.
> > > ---
> > >  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);
>
> Took a while for me to find the right device and setup the proper
> system for the testing. This block missing the serial number:
>
>         input_event(input, EV_MSC, MSC_SERIAL, 0);
>
> Without this line, the next tool will not get its serial number.

I am tempted to simply disregard this request. It has been known for
ages that the evdev values are cached, so if you do not have the value
you need that means that the value has been sent previously (or you
can request it upon start with an ioctl). So in this particular case,
I don't really see the logic in forcing the SERIAL into the TOOL type
when the tool is clearly unrelated to the serial.

My fear here is that by linking together too many axes, we may enter
in a state where we can not untangle them when needed.

>
> > > +       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;
>
> This case should return before HID_DG_INVERT is checked since we may
> get TIPSWITCH bit before INVERT. In fact, the device that I tested
> sends the tipswatch bit before the invert bit. So, I alway get a PEN
> in and out before I get ERASER events, when I bring the pen in with
> the side-switch/invert bit pressed.
>
> However, we know not all devices support INVERT. We probably have to
> keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> wait until HID_DG_INVERT is reached.

I am under the impression that you completely missed the point of the
patch series. This series re-orders the processing of the events, and
if you look at the very first hunk in this patch, you'll see that the
new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
matter the order of the device.

So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
is set, either INVERT or ERASER is set to 1, whether or not they come
before or after in the report.

>
> If you are interested in the evtest output, please let me know. I'll
> share it with you offline so we don't abuse this list...

evtest is the output of the kernel, and it doesn't give me much more
than "it's broken". However, if you can give me the hid-recorder
outputs, I'll be able to reproduce locally and compare the output as I
fix the code. Of course the best would be to add test cases in the
hid-tools repo, but I'll need the hid-recorder anyway to understand
what is failing and to be able to write the tests.

Cheers,
Benjamin

>
> Cheers,
> Ping
>
> > > +               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
> > > --
> > > 2.33.1
> > >
>


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-14 10:23       ` Benjamin Tissoires
@ 2022-02-15  2:04         ` Ping Cheng
  2022-02-15  8:51           ` Benjamin Tissoires
  0 siblings, 1 reply; 23+ messages in thread
From: Ping Cheng @ 2022-02-15  2:04 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, open list:HID CORE LAYER, Linux Doc Mailing List,
	lkml

On Mon, Feb 14, 2022 at 2:23 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> Hi Ping,
>
> On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
> >
> > Sorry for the noise. Hit the wrong buttons...
> >
> > On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> > >
> > > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > > <benjamin.tissoires@redhat.com> wrote:
> > > >
> > > > 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 <benjamin.tissoires@redhat.com>
> > > >
> > > > ---
> > > >
> > > > Changes in v2:
> > > > - rework the entire tool switching, this makes the processing
> > > >   slightly more complex but is better for existing userspace.
> > > > ---
> > > >  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);
> >
> > Took a while for me to find the right device and setup the proper
> > system for the testing. This block missing the serial number:
> >
> >         input_event(input, EV_MSC, MSC_SERIAL, 0);
> >
> > Without this line, the next tool will not get its serial number.
>
> I am tempted to simply disregard this request. It has been known for
> ages that the evdev values are cached, so if you do not have the value
> you need that means that the value has been sent previously (or you
> can request it upon start with an ioctl). So in this particular case,
> I don't really see the logic in forcing the SERIAL into the TOOL type
> when the tool is clearly unrelated to the serial.
>
> My fear here is that by linking together too many axes, we may enter
> in a state where we can not untangle them when needed.

I see your point. We indeed added those ioctl's in the X driver to
avoid missing the initial states of some of the key events.

> >
> > > > +       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;
> >
> > This case should return before HID_DG_INVERT is checked since we may
> > get TIPSWITCH bit before INVERT. In fact, the device that I tested
> > sends the tipswatch bit before the invert bit. So, I alway get a PEN
> > in and out before I get ERASER events, when I bring the pen in with
> > the side-switch/invert bit pressed.
> >
> > However, we know not all devices support INVERT. We probably have to
> > keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> > wait until HID_DG_INVERT is reached.
>
> I am under the impression that you completely missed the point of the
> patch series. This series re-orders the processing of the events, and
> if you look at the very first hunk in this patch, you'll see that the
> new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
> matter the order of the device.

Yeah, I read that part of the code, more than once. But, my evtest
gave me an extra set of TOOL_PEN events before TOOL_ERASER. I was
confused too. Then I thought maybe the code still relies on the actual
order of the usages. Anyway, we've done enough discussion and testing,
let's move on. The patchset is:

Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
Tested-by: Ping Cheng <ping.cheng@wacom.com>

Thank you for your effort, Benjamin!
Ping

> So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
> is set, either INVERT or ERASER is set to 1, whether or not they come
> before or after in the report.
>
> >
> > If you are interested in the evtest output, please let me know. I'll
> > share it with you offline so we don't abuse this list...
>
> evtest is the output of the kernel, and it doesn't give me much more
> than "it's broken". However, if you can give me the hid-recorder
> outputs, I'll be able to reproduce locally and compare the output as I
> fix the code. Of course the best would be to add test cases in the
> hid-tools repo, but I'll need the hid-recorder anyway to understand
> what is failing and to be able to write the tests.
>
> Cheers,
> Benjamin
>
> >
> > Cheers,
> > Ping
> >
> > > > +               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
> > > > --
> > > > 2.33.1
> > > >
> >
>

^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-15  2:04         ` Ping Cheng
@ 2022-02-15  8:51           ` Benjamin Tissoires
  2022-02-16 12:42             ` Benjamin Tissoires
  0 siblings, 1 reply; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-15  8:51 UTC (permalink / raw)
  To: Ping Cheng
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, open list:HID CORE LAYER, Linux Doc Mailing List,
	lkml

On Tue, Feb 15, 2022 at 3:04 AM Ping Cheng <pinglinux@gmail.com> wrote:
>
> On Mon, Feb 14, 2022 at 2:23 AM Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
> >
> > Hi Ping,
> >
> > On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
> > >
> > > Sorry for the noise. Hit the wrong buttons...
> > >
> > > On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> > > >
> > > > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > > > <benjamin.tissoires@redhat.com> wrote:
> > > > >
> > > > > 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 <benjamin.tissoires@redhat.com>
> > > > >
> > > > > ---
> > > > >
> > > > > Changes in v2:
> > > > > - rework the entire tool switching, this makes the processing
> > > > >   slightly more complex but is better for existing userspace.
> > > > > ---
> > > > >  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);
> > >
> > > Took a while for me to find the right device and setup the proper
> > > system for the testing. This block missing the serial number:
> > >
> > >         input_event(input, EV_MSC, MSC_SERIAL, 0);
> > >
> > > Without this line, the next tool will not get its serial number.
> >
> > I am tempted to simply disregard this request. It has been known for
> > ages that the evdev values are cached, so if you do not have the value
> > you need that means that the value has been sent previously (or you
> > can request it upon start with an ioctl). So in this particular case,
> > I don't really see the logic in forcing the SERIAL into the TOOL type
> > when the tool is clearly unrelated to the serial.
> >
> > My fear here is that by linking together too many axes, we may enter
> > in a state where we can not untangle them when needed.
>
> I see your point. We indeed added those ioctl's in the X driver to
> avoid missing the initial states of some of the key events.
>
> > >
> > > > > +       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;
> > >
> > > This case should return before HID_DG_INVERT is checked since we may
> > > get TIPSWITCH bit before INVERT. In fact, the device that I tested
> > > sends the tipswatch bit before the invert bit. So, I alway get a PEN
> > > in and out before I get ERASER events, when I bring the pen in with
> > > the side-switch/invert bit pressed.
> > >
> > > However, we know not all devices support INVERT. We probably have to
> > > keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> > > wait until HID_DG_INVERT is reached.
> >
> > I am under the impression that you completely missed the point of the
> > patch series. This series re-orders the processing of the events, and
> > if you look at the very first hunk in this patch, you'll see that the
> > new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
> > matter the order of the device.
>
> Yeah, I read that part of the code, more than once. But, my evtest
> gave me an extra set of TOOL_PEN events before TOOL_ERASER. I was
> confused too. Then I thought maybe the code still relies on the actual
> order of the usages. Anyway, we've done enough discussion and testing,
> let's move on. The patchset is:
>
> Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
> Tested-by: Ping Cheng <ping.cheng@wacom.com>

Thanks for the review.

 However, if the device is not working as expected, can you send me
the hid-recorder[0] output off list so I can diagnose what is
happening?

Cheers,
Benjamin

[0] clone https://gitlab.freedesktop.org/libevdev/hid-tools, then pip
install ., then `sudo hid-recorder`

>
> Thank you for your effort, Benjamin!
> Ping
>
> > So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
> > is set, either INVERT or ERASER is set to 1, whether or not they come
> > before or after in the report.
> >
> > >
> > > If you are interested in the evtest output, please let me know. I'll
> > > share it with you offline so we don't abuse this list...
> >
> > evtest is the output of the kernel, and it doesn't give me much more
> > than "it's broken". However, if you can give me the hid-recorder
> > outputs, I'll be able to reproduce locally and compare the output as I
> > fix the code. Of course the best would be to add test cases in the
> > hid-tools repo, but I'll need the hid-recorder anyway to understand
> > what is failing and to be able to write the tests.
> >
> > Cheers,
> > Benjamin
> >
> > >
> > > Cheers,
> > > Ping
> > >
> > > > > +               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
> > > > > --
> > > > > 2.33.1
> > > > >
> > >
> >
>


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 12/12] Input: docs: add more details on the use of BTN_TOOL
  2022-02-03 14:32 ` [PATCH v2 12/12] Input: docs: add more details on the use of BTN_TOOL Benjamin Tissoires
@ 2022-02-16  5:40   ` Peter Hutterer
  0 siblings, 0 replies; 23+ messages in thread
From: Peter Hutterer @ 2022-02-16  5:40 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Ping Cheng, Aaron Armstrong Skomra,
	Jason Gerecke, linux-input, linux-doc, linux-kernel

On Thu, Feb 03, 2022 at 03:32:26PM +0100, Benjamin Tissoires wrote:
> 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 <benjamin.tissoires@redhat.com>
> 
> ---
> 
> changes in v2:
> - changed to explain that switching tool in one EV_SYN report
>   is not nice for userspace
> ---
>  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_<name> code should be reset to 0. All
>      trackpads, tablets, and touchscreens should use at least one BTN_TOOL_<name>
> -    code when events are generated.
> +    code when events are generated. Likewise all trackpads, tablets, and
> +    touchscreens should export only one BTN_TOOL_<name> at a time. To not break

I still think s/export/set to nonzero/ to avoid any ambiguity with setting the
evbit on the device vs setting the value to nonzero here, but the remainder is
good, thanks :)

Acked-by: Peter Hutterer <peter.hutterer@who-t.net>

Cheers,
  Peter


> +    existing userspace, it is recommended to not switch tool in one EV_SYN frame
> +    but first emitting the old BTN_TOOL_<name> at 0, then emit one SYN_REPORT
> +    and then set the new BTN_TOOL_<name> at 1.
>  
>  * BTN_TOUCH:
>  
> -- 
> 2.33.1
> 

^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-15  8:51           ` Benjamin Tissoires
@ 2022-02-16 12:42             ` Benjamin Tissoires
  2022-02-17  1:27               ` Ping Cheng
  0 siblings, 1 reply; 23+ messages in thread
From: Benjamin Tissoires @ 2022-02-16 12:42 UTC (permalink / raw)
  To: Ping Cheng
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, open list:HID CORE LAYER, Linux Doc Mailing List,
	lkml

Hi Ping,

[bringing back the public ML]

On Tue, Feb 15, 2022 at 9:51 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> On Tue, Feb 15, 2022 at 3:04 AM Ping Cheng <pinglinux@gmail.com> wrote:
> >
> > On Mon, Feb 14, 2022 at 2:23 AM Benjamin Tissoires
> > <benjamin.tissoires@redhat.com> wrote:
> > >
> > > Hi Ping,
> > >
> > > On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
> > > >
> > > > Sorry for the noise. Hit the wrong buttons...
> > > >
> > > > On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> > > > >
> > > > > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > > > > <benjamin.tissoires@redhat.com> wrote:
> > > > > >
> > > > > > 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 <benjamin.tissoires@redhat.com>
> > > > > >
> > > > > > ---
> > > > > >
> > > > > > Changes in v2:
> > > > > > - rework the entire tool switching, this makes the processing
> > > > > >   slightly more complex but is better for existing userspace.
> > > > > > ---
> > > > > >  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);
> > > >
> > > > Took a while for me to find the right device and setup the proper
> > > > system for the testing. This block missing the serial number:
> > > >
> > > >         input_event(input, EV_MSC, MSC_SERIAL, 0);
> > > >
> > > > Without this line, the next tool will not get its serial number.
> > >
> > > I am tempted to simply disregard this request. It has been known for
> > > ages that the evdev values are cached, so if you do not have the value
> > > you need that means that the value has been sent previously (or you
> > > can request it upon start with an ioctl). So in this particular case,
> > > I don't really see the logic in forcing the SERIAL into the TOOL type
> > > when the tool is clearly unrelated to the serial.
> > >
> > > My fear here is that by linking together too many axes, we may enter
> > > in a state where we can not untangle them when needed.
> >
> > I see your point. We indeed added those ioctl's in the X driver to
> > avoid missing the initial states of some of the key events.
> >
> > > >
> > > > > > +       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;
> > > >
> > > > This case should return before HID_DG_INVERT is checked since we may
> > > > get TIPSWITCH bit before INVERT. In fact, the device that I tested
> > > > sends the tipswatch bit before the invert bit. So, I alway get a PEN
> > > > in and out before I get ERASER events, when I bring the pen in with
> > > > the side-switch/invert bit pressed.
> > > >
> > > > However, we know not all devices support INVERT. We probably have to
> > > > keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> > > > wait until HID_DG_INVERT is reached.
> > >
> > > I am under the impression that you completely missed the point of the
> > > patch series. This series re-orders the processing of the events, and
> > > if you look at the very first hunk in this patch, you'll see that the
> > > new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
> > > matter the order of the device.
> >
> > Yeah, I read that part of the code, more than once. But, my evtest
> > gave me an extra set of TOOL_PEN events before TOOL_ERASER. I was
> > confused too. Then I thought maybe the code still relies on the actual
> > order of the usages. Anyway, we've done enough discussion and testing,
> > let's move on. The patchset is:
> >
> > Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
> > Tested-by: Ping Cheng <ping.cheng@wacom.com>
>
> Thanks for the review.
>
>  However, if the device is not working as expected, can you send me
> the hid-recorder[0] output off list so I can diagnose what is
> happening?

Thanks for sending me the records (privately).

And a quick look at it and it explained that spurious BTN_TOOL change.
If you look at the recordings where you take the stylus in proximity
with the eraser button pressed, you'll see:

# ReportID: 20 / Tip Switch: 0 | Barrel Switch: 0 | Eraser: 0 |
Invert: 0 | Secondary Barrel Switch: 0 | In Range: 1 | # | X:  18699 |
Y:  11537 | Tip Pressure:      0 | 0xff00005b: -32661 | Transducer
Serial Number:   509392226 | Undefined:    1 | Battery Strength:  255
| X Tilt:   23 | Y Tilt:    0
E: 000000.000000 18 14 20 0b 49 11 2d 00 00 6b 80 62 b5 5c 1e 01 ff 17 00
# ReportID: 20 / Tip Switch: 0 | Barrel Switch: 0 | Eraser: 0 |
Invert: 0 | Secondary Barrel Switch: 0 | In Range: 0 | # | X:  18699 |
Y:  11537 | Tip Pressure:      0 | 0xff00005b: -32661 | Transducer
Serial Number:   509392226 | Undefined:    1 | Battery Strength:    0
| X Tilt:   23 | Y Tilt:    0
E: 000000.001988 18 14 00 0b 49 11 2d 00 00 6b 80 62 b5 5c 1e 01 00 17 00
# ReportID: 20 / Tip Switch: 0 | Barrel Switch: 0 | Eraser: 0 |
Invert: 1 | Secondary Barrel Switch: 0 | In Range: 1 | # | X:  18696 |
Y:  11543 | Tip Pressure:      0 | 0xff00005b: -32661 | Transducer
Serial Number:   509392226 | Undefined:    1 | Battery Strength:    0
| X Tilt:   23 | Y Tilt:    0
E: 000000.003002 18 14 28 08 49 17 2d 00 00 6b 80 62 b5 5c 1e 01 00 17 00

So the firmware first emits a tip event (Eraser: 0 | Invert: 0 | In
Range: 1), then realizes there is an invert incoming so it sends an
out of prox (Eraser: 0 | Invert: 0 | In Range: 0) and then the eraser
in (Eraser: 0 | Invert: 1 | In Range: 1).

So:
- your pen is actually following the spec from Microsoft, i.e., it
doesn't switch from in-range without erasing to in-range with erasing
without going through out-of-prox, which means it is probably well
supported in the Windows world
- your firmware is not fast enough to detect the invert bit and papers
over it (but honestly, who cares that this quick event comes in).

There is not much we can do, so I consider this "failure" to be
expected and the code is behaving properly.

Cheers,
Benjamin

>
> Cheers,
> Benjamin
>
> [0] clone https://gitlab.freedesktop.org/libevdev/hid-tools, then pip
> install ., then `sudo hid-recorder`
>
> >
> > Thank you for your effort, Benjamin!
> > Ping
> >
> > > So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
> > > is set, either INVERT or ERASER is set to 1, whether or not they come
> > > before or after in the report.
> > >
> > > >
> > > > If you are interested in the evtest output, please let me know. I'll
> > > > share it with you offline so we don't abuse this list...
> > >
> > > evtest is the output of the kernel, and it doesn't give me much more
> > > than "it's broken". However, if you can give me the hid-recorder
> > > outputs, I'll be able to reproduce locally and compare the output as I
> > > fix the code. Of course the best would be to add test cases in the
> > > hid-tools repo, but I'll need the hid-recorder anyway to understand
> > > what is failing and to be able to write the tests.
> > >
> > > Cheers,
> > > Benjamin
> > >
> > > >
> > > > Cheers,
> > > > Ping
> > > >
> > > > > > +               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
> > > > > > --
> > > > > > 2.33.1
> > > > > >
> > > >
> > >
> >


^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT
  2022-02-16 12:42             ` Benjamin Tissoires
@ 2022-02-17  1:27               ` Ping Cheng
  0 siblings, 0 replies; 23+ messages in thread
From: Ping Cheng @ 2022-02-17  1:27 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Jiri Kosina, Dmitry Torokhov, Jonathan Corbet,
	Ahelenia Ziemiańska, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, open list:HID CORE LAYER, Linux Doc Mailing List,
	lkml

On Wed, Feb 16, 2022 at 4:43 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> Hi Ping,
>
> [bringing back the public ML]
>
> On Tue, Feb 15, 2022 at 9:51 AM Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
> >
> > On Tue, Feb 15, 2022 at 3:04 AM Ping Cheng <pinglinux@gmail.com> wrote:
> > >
> > > On Mon, Feb 14, 2022 at 2:23 AM Benjamin Tissoires
> > > <benjamin.tissoires@redhat.com> wrote:
> > > >
> > > > Hi Ping,
> > > >
> > > > On Thu, Feb 10, 2022 at 6:44 AM Ping Cheng <pinglinux@gmail.com> wrote:
> > > > >
> > > > > Sorry for the noise. Hit the wrong buttons...
> > > > >
> > > > > On Wed, Feb 9, 2022 at 9:21 PM Ping Cheng <pinglinux@gmail.com> wrote:
> > > > > >
> > > > > > On Thu, Feb 3, 2022 at 6:33 AM Benjamin Tissoires
> > > > > > <benjamin.tissoires@redhat.com> wrote:
> > > > > > >
> > > > > > > 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 <benjamin.tissoires@redhat.com>
> > > > > > >
> > > > > > > ---
> > > > > > >
> > > > > > > Changes in v2:
> > > > > > > - rework the entire tool switching, this makes the processing
> > > > > > >   slightly more complex but is better for existing userspace.
> > > > > > > ---
> > > > > > >  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);
> > > > >
> > > > > Took a while for me to find the right device and setup the proper
> > > > > system for the testing. This block missing the serial number:
> > > > >
> > > > >         input_event(input, EV_MSC, MSC_SERIAL, 0);
> > > > >
> > > > > Without this line, the next tool will not get its serial number.
> > > >
> > > > I am tempted to simply disregard this request. It has been known for
> > > > ages that the evdev values are cached, so if you do not have the value
> > > > you need that means that the value has been sent previously (or you
> > > > can request it upon start with an ioctl). So in this particular case,
> > > > I don't really see the logic in forcing the SERIAL into the TOOL type
> > > > when the tool is clearly unrelated to the serial.
> > > >
> > > > My fear here is that by linking together too many axes, we may enter
> > > > in a state where we can not untangle them when needed.
> > >
> > > I see your point. We indeed added those ioctl's in the X driver to
> > > avoid missing the initial states of some of the key events.
> > >
> > > > >
> > > > > > > +       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;
> > > > >
> > > > > This case should return before HID_DG_INVERT is checked since we may
> > > > > get TIPSWITCH bit before INVERT. In fact, the device that I tested
> > > > > sends the tipswatch bit before the invert bit. So, I alway get a PEN
> > > > > in and out before I get ERASER events, when I bring the pen in with
> > > > > the side-switch/invert bit pressed.
> > > > >
> > > > > However, we know not all devices support INVERT. We probably have to
> > > > > keep the invert quirk to decide if BTN_TOOL_PEN should be set here or
> > > > > wait until HID_DG_INVERT is reached.
> > > >
> > > > I am under the impression that you completely missed the point of the
> > > > patch series. This series re-orders the processing of the events, and
> > > > if you look at the very first hunk in this patch, you'll see that the
> > > > new processing ensures we treat INVERT and ERASER before TIPSWITCH, no
> > > > matter the order of the device.
> > >
> > > Yeah, I read that part of the code, more than once. But, my evtest
> > > gave me an extra set of TOOL_PEN events before TOOL_ERASER. I was
> > > confused too. Then I thought maybe the code still relies on the actual
> > > order of the usages. Anyway, we've done enough discussion and testing,
> > > let's move on. The patchset is:
> > >
> > > Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
> > > Tested-by: Ping Cheng <ping.cheng@wacom.com>
> >
> > Thanks for the review.
> >
> >  However, if the device is not working as expected, can you send me
> > the hid-recorder[0] output off list so I can diagnose what is
> > happening?
>
> Thanks for sending me the records (privately).
>
> And a quick look at it and it explained that spurious BTN_TOOL change.
> If you look at the recordings where you take the stylus in proximity
> with the eraser button pressed, you'll see:
>
> # ReportID: 20 / Tip Switch: 0 | Barrel Switch: 0 | Eraser: 0 |
> Invert: 0 | Secondary Barrel Switch: 0 | In Range: 1 | # | X:  18699 |
> Y:  11537 | Tip Pressure:      0 | 0xff00005b: -32661 | Transducer
> Serial Number:   509392226 | Undefined:    1 | Battery Strength:  255
> | X Tilt:   23 | Y Tilt:    0
> E: 000000.000000 18 14 20 0b 49 11 2d 00 00 6b 80 62 b5 5c 1e 01 ff 17 00
> # ReportID: 20 / Tip Switch: 0 | Barrel Switch: 0 | Eraser: 0 |
> Invert: 0 | Secondary Barrel Switch: 0 | In Range: 0 | # | X:  18699 |
> Y:  11537 | Tip Pressure:      0 | 0xff00005b: -32661 | Transducer
> Serial Number:   509392226 | Undefined:    1 | Battery Strength:    0
> | X Tilt:   23 | Y Tilt:    0
> E: 000000.001988 18 14 00 0b 49 11 2d 00 00 6b 80 62 b5 5c 1e 01 00 17 00
> # ReportID: 20 / Tip Switch: 0 | Barrel Switch: 0 | Eraser: 0 |
> Invert: 1 | Secondary Barrel Switch: 0 | In Range: 1 | # | X:  18696 |
> Y:  11543 | Tip Pressure:      0 | 0xff00005b: -32661 | Transducer
> Serial Number:   509392226 | Undefined:    1 | Battery Strength:    0
> | X Tilt:   23 | Y Tilt:    0
> E: 000000.003002 18 14 28 08 49 17 2d 00 00 6b 80 62 b5 5c 1e 01 00 17 00
>
> So the firmware first emits a tip event (Eraser: 0 | Invert: 0 | In
> Range: 1), then realizes there is an invert incoming so it sends an
> out of prox (Eraser: 0 | Invert: 0 | In Range: 0) and then the eraser
> in (Eraser: 0 | Invert: 1 | In Range: 1).
>
> So:
> - your pen is actually following the spec from Microsoft, i.e., it
> doesn't switch from in-range without erasing to in-range with erasing
> without going through out-of-prox, which means it is probably well
> supported in the Windows world
> - your firmware is not fast enough to detect the invert bit and papers
> over it (but honestly, who cares that this quick event comes in).
>
> There is not much we can do, so I consider this "failure" to be
> expected and the code is behaving properly.

Well done, Benjamin! The patchset is ready. Whoever is responsible for
merging it, please do so.

Cheers,
Ping

> > [0] clone https://gitlab.freedesktop.org/libevdev/hid-tools, then pip
> > install ., then `sudo hid-recorder`
> >
> > >
> > > Thank you for your effort, Benjamin!
> > > Ping
> > >
> > > > So when we process TIPSWITCH here, we are sure that if BTN_TOOL_RUBBER
> > > > is set, either INVERT or ERASER is set to 1, whether or not they come
> > > > before or after in the report.
> > > >
> > > > >
> > > > > If you are interested in the evtest output, please let me know. I'll
> > > > > share it with you offline so we don't abuse this list...
> > > >
> > > > evtest is the output of the kernel, and it doesn't give me much more
> > > > than "it's broken". However, if you can give me the hid-recorder
> > > > outputs, I'll be able to reproduce locally and compare the output as I
> > > > fix the code. Of course the best would be to add test cases in the
> > > > hid-tools repo, but I'll need the hid-recorder anyway to understand
> > > > what is failing and to be able to write the tests.
> > > >
> > > > Cheers,
> > > > Benjamin
> > > >
> > > > >
> > > > > Cheers,
> > > > > Ping
> > > > >
> > > > > > > +               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
> > > > > > > --
> > > > > > > 2.33.1
> > > > > > >
> > > > >
> > > >
> > >
>

^ permalink raw reply	[flat|nested] 23+ messages in thread

* Re: [PATCH v2 00/12] HID: fix for generic input processing
  2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
                   ` (11 preceding siblings ...)
  2022-02-03 14:32 ` [PATCH v2 12/12] Input: docs: add more details on the use of BTN_TOOL Benjamin Tissoires
@ 2022-03-01 14:53 ` Jiri Kosina
  12 siblings, 0 replies; 23+ messages in thread
From: Jiri Kosina @ 2022-03-01 14:53 UTC (permalink / raw)
  To: Benjamin Tissoires
  Cc: Dmitry Torokhov, Jonathan Corbet, Ahelenia Ziemiańska,
	Ping Cheng, Aaron Armstrong Skomra, Jason Gerecke,
	Peter Hutterer, linux-input, linux-doc, linux-kernel

On Thu, 3 Feb 2022, Benjamin Tissoires wrote:

> Hi,
> 
> this is the v2 of my series which reworks the HID report processing.
> 
> I took Ping's comments into account, and amended my MR with the
> regression tests[0].
> More specifically, the tests (and thus this new version of the series)
> enforces that only one BTN_TOOL_* event gets forwarded between each
> EV_SYN frame, and that BTN_TOUCH are properly translated too.
> 
> This also magivally solved some worrying transitions we had in the
> pen state machine where the pen was jumping from "eraser" to "in
> contact". This new behavior enforces a "out-of-range" state in the
> middle, making it easier for userspace to understand now.
> 
> Again, tests are welcome :)
> 
> Cheers,
> Benjamin
> 
> [0] https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/127
> 
> Benjamin Tissoires (12):
>   HID: core: statically allocate read buffers
>   HID: core: de-duplicate some code in hid_input_field()
>   HID: core: split data fetching from processing in hid_input_field()
>   HID: input: tag touchscreens as such if the physical is not there
>   HID: input: rework spaghetti code with switch statements
>   HID: input: move up out-of-range processing of input values
>   HID: compute an ordered list of input fields to process
>   HID: core: for input reports, process the usages by priority list
>   HID: input: enforce Invert usage to be processed before InRange
>   HID: input: remove the need for HID_QUIRK_INVERT
>   HID: input: accommodate priorities for slotted devices
>   Input: docs: add more details on the use of BTN_TOOL
> 
>  Documentation/input/event-codes.rst |   6 +-
>  drivers/hid/hid-core.c              | 280 ++++++++++++++++++---
>  drivers/hid/hid-input.c             | 364 ++++++++++++++++++++++------
>  include/linux/hid.h                 |  23 +-
>  4 files changed, 568 insertions(+), 105 deletions(-)

This is now in hid.git#for-5.18/core.

Thanks a lot Benjamin, very nice work.

-- 
Jiri Kosina
SUSE Labs


^ permalink raw reply	[flat|nested] 23+ messages in thread

end of thread, other threads:[~2022-03-01 14:53 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-03 14:32 [PATCH v2 00/12] HID: fix for generic input processing Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 01/12] HID: core: statically allocate read buffers Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 02/12] HID: core: de-duplicate some code in hid_input_field() Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 03/12] HID: core: split data fetching from processing " Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 04/12] HID: input: tag touchscreens as such if the physical is not there Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 05/12] HID: input: rework spaghetti code with switch statements Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 06/12] HID: input: move up out-of-range processing of input values Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 07/12] HID: compute an ordered list of input fields to process Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 08/12] HID: core: for input reports, process the usages by priority list Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 09/12] HID: input: enforce Invert usage to be processed before InRange Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 10/12] HID: input: remove the need for HID_QUIRK_INVERT Benjamin Tissoires
2022-02-04  1:41   ` Ping Cheng
2022-02-10  5:21   ` Ping Cheng
2022-02-10  5:43     ` Ping Cheng
2022-02-14 10:23       ` Benjamin Tissoires
2022-02-15  2:04         ` Ping Cheng
2022-02-15  8:51           ` Benjamin Tissoires
2022-02-16 12:42             ` Benjamin Tissoires
2022-02-17  1:27               ` Ping Cheng
2022-02-03 14:32 ` [PATCH v2 11/12] HID: input: accommodate priorities for slotted devices Benjamin Tissoires
2022-02-03 14:32 ` [PATCH v2 12/12] Input: docs: add more details on the use of BTN_TOOL Benjamin Tissoires
2022-02-16  5:40   ` Peter Hutterer
2022-03-01 14:53 ` [PATCH v2 00/12] HID: fix for generic input processing Jiri Kosina

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