HID: logitech-hidpp: do not hardcode very long report length

The HID++ spec says the following about the very long report length:
"n Bytes, depends on HID++ collection declaration".

Hardcoding this breaks talking to some HID++ devices over BlueTooth, since
they declare only 45 bytes data for the very long report, rather then the
hardcoded 63.

This commit fixes this by getting the actual report length from the
descriptors.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

1 files changed, 32 insertions, 18 deletions

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index e8a552c8801d..ecf1b1e22e1a 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -51,7 +51,7 @@ MODULE_PARM_DESC(disable_tap_to_click,
 
 #define HIDPP_REPORT_SHORT_LENGTH		7
 #define HIDPP_REPORT_LONG_LENGTH		20
-#define HIDPP_REPORT_VERY_LONG_LENGTH		64
+#define HIDPP_REPORT_VERY_LONG_MAX_LENGTH	64
 
 #define HIDPP_QUIRK_CLASS_WTP			BIT(0)
 #define HIDPP_QUIRK_CLASS_M560			BIT(1)
@@ -106,13 +106,13 @@ MODULE_PARM_DESC(disable_tap_to_click,
 struct fap {
 	u8 feature_index;
 	u8 funcindex_clientid;
-	u8 params[HIDPP_REPORT_VERY_LONG_LENGTH - 4U];
+	u8 params[HIDPP_REPORT_VERY_LONG_MAX_LENGTH - 4U];
 };
 
 struct rap {
 	u8 sub_id;
 	u8 reg_address;
-	u8 params[HIDPP_REPORT_VERY_LONG_LENGTH - 4U];
+	u8 params[HIDPP_REPORT_VERY_LONG_MAX_LENGTH - 4U];
 };
 
 struct hidpp_report {
@@ -162,6 +162,7 @@ struct hidpp_device {
 	void *send_receive_buf;
 	char *name;		/* will never be NULL and should not be freed */
 	wait_queue_head_t wait;
+	int very_long_report_length;
 	bool answer_available;
 	u8 protocol_major;
 	u8 protocol_minor;
@@ -214,7 +215,7 @@ static int __hidpp_send_report(struct hid_device *hdev,
 		fields_count = HIDPP_REPORT_LONG_LENGTH;
 		break;
 	case REPORT_ID_HIDPP_VERY_LONG:
-		fields_count = HIDPP_REPORT_VERY_LONG_LENGTH;
+		fields_count = hidpp->very_long_report_length;
 		break;
 	default:
 		return -ENODEV;
@@ -340,7 +341,7 @@ static int hidpp_send_rap_command_sync(struct hidpp_device *hidpp_dev,
 		max_count = HIDPP_REPORT_LONG_LENGTH - 4;
 		break;
 	case REPORT_ID_HIDPP_VERY_LONG:
-		max_count = HIDPP_REPORT_VERY_LONG_LENGTH - 4;
+		max_count = hidpp_dev->very_long_report_length - 4;
 		break;
 	default:
 		return -EINVAL;
@@ -934,7 +935,7 @@ static int hidpp_devicenametype_get_device_name(struct hidpp_device *hidpp,
 
 	switch (response.report_id) {
 	case REPORT_ID_HIDPP_VERY_LONG:
-		count = HIDPP_REPORT_VERY_LONG_LENGTH - 4;
+		count = hidpp->very_long_report_length - 4;
 		break;
 	case REPORT_ID_HIDPP_LONG:
 		count = HIDPP_REPORT_LONG_LENGTH - 4;
@@ -2923,7 +2924,7 @@ static int hidpp_raw_event(struct hid_device *hdev, struct hid_report *report,
 	/* Generic HID++ processing. */
 	switch (data[0]) {
 	case REPORT_ID_HIDPP_VERY_LONG:
-		if (size != HIDPP_REPORT_VERY_LONG_LENGTH) {
+		if (size != hidpp->very_long_report_length) {
 			hid_err(hdev, "received hid++ report of bad size (%d)",
 				size);
 			return 1;
@@ -3226,24 +3227,34 @@ static const struct attribute_group ps_attribute_group = {
 	.attrs = sysfs_attrs
 };
 
-static bool hidpp_validate_report(struct hid_device *hdev, int id, int size,
-		bool optional)
+static int hidpp_get_report_length(struct hid_device *hdev, int id)
 {
 	struct hid_report_enum *re;
 	struct hid_report *report;
 
+	re = &(hdev->report_enum[HID_OUTPUT_REPORT]);
+	report = re->report_id_hash[id];
+	if (!report)
+		return 0;
+
+	return report->field[0]->report_count + 1;
+}
+
+static bool hidpp_validate_report(struct hid_device *hdev, int id,
+				  int expected_length, bool optional)
+{
+	int report_length;
+
 	if (id >= HID_MAX_IDS || id < 0) {
 		hid_err(hdev, "invalid HID report id %u\n", id);
 		return false;
 	}
 
-	re = &(hdev->report_enum[HID_OUTPUT_REPORT]);
-	report = re->report_id_hash[id];
-
-	if (!report)
+	report_length = hidpp_get_report_length(hdev, id);
+	if (!report_length)
 		return optional;
 
-	if (report->field[0]->report_count < size) {
+	if (report_length < expected_length) {
 		hid_warn(hdev, "not enough values in hidpp report %d\n", id);
 		return false;
 	}
@@ -3254,11 +3265,9 @@ static bool hidpp_validate_report(struct hid_device *hdev, int id, int size,
 static bool hidpp_validate_device(struct hid_device *hdev)
 {
 	return hidpp_validate_report(hdev, REPORT_ID_HIDPP_SHORT,
-				     HIDPP_REPORT_SHORT_LENGTH - 1, false) &&
+				     HIDPP_REPORT_SHORT_LENGTH, false) &&
 	       hidpp_validate_report(hdev, REPORT_ID_HIDPP_LONG,
-				     HIDPP_REPORT_LONG_LENGTH - 1, true) &&
-	       hidpp_validate_report(hdev, REPORT_ID_HIDPP_VERY_LONG,
-				     HIDPP_REPORT_VERY_LONG_LENGTH - 1, true);
+				     HIDPP_REPORT_LONG_LENGTH, true);
 }
 
 static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
@@ -3291,6 +3300,11 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	hidpp->quirks = id->driver_data;
 
+	hidpp->very_long_report_length =
+		hidpp_get_report_length(hdev, REPORT_ID_HIDPP_VERY_LONG);
+	if (hidpp->very_long_report_length > HIDPP_REPORT_VERY_LONG_MAX_LENGTH)
+		hidpp->very_long_report_length = HIDPP_REPORT_VERY_LONG_MAX_LENGTH;
+
 	if (id->group == HID_GROUP_LOGITECH_DJ_DEVICE)
 		hidpp->quirks |= HIDPP_QUIRK_UNIFYING;