From d43c17ead879ba7c076dc2f5fd80cd76047c9ff4 Mon Sep 17 00:00:00 2001
From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Date: Wed, 3 Apr 2019 16:20:20 +0200
Subject: HID: input: make sure the wheel high resolution multiplier is set

Some old mice have a tendency to not accept the high resolution multiplier.
They reply with a -EPIPE which was previously ignored.

Force the call to resolution multiplier to be synchronous and actually
check for the answer. If this fails, consider the mouse like a normal one.

Fixes: 2dc702c991e377 ("HID: input: use the Resolution Multiplier for
       high-resolution scrolling")
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1700071
Reported-and-tested-by: James Feeney <james@nurealm.net>
Cc: stable@vger.kernel.org  # v5.0+
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
 drivers/hid/hid-input.c | 81 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 50 insertions(+), 31 deletions(-)

(limited to 'drivers/hid/hid-input.c')

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 1fce0076e7dc..fadf76f0a386 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -1542,52 +1542,71 @@ static void hidinput_close(struct input_dev *dev)
 	hid_hw_close(hid);
 }
 
-static void hidinput_change_resolution_multipliers(struct hid_device *hid)
+static bool __hidinput_change_resolution_multipliers(struct hid_device *hid,
+		struct hid_report *report, bool use_logical_max)
 {
-	struct hid_report_enum *rep_enum;
-	struct hid_report *rep;
 	struct hid_usage *usage;
+	bool update_needed = false;
 	int i, j;
 
-	rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
-	list_for_each_entry(rep, &rep_enum->report_list, list) {
-		bool update_needed = false;
+	if (report->maxfield == 0)
+		return false;
 
-		if (rep->maxfield == 0)
-			continue;
+	/*
+	 * If we have more than one feature within this report we
+	 * need to fill in the bits from the others before we can
+	 * overwrite the ones for the Resolution Multiplier.
+	 */
+	if (report->maxfield > 1) {
+		hid_hw_request(hid, report, HID_REQ_GET_REPORT);
+		hid_hw_wait(hid);
+	}
 
-		/*
-		 * If we have more than one feature within this report we
-		 * need to fill in the bits from the others before we can
-		 * overwrite the ones for the Resolution Multiplier.
+	for (i = 0; i < report->maxfield; i++) {
+		__s32 value = use_logical_max ?
+			      report->field[i]->logical_maximum :
+			      report->field[i]->logical_minimum;
+
+		/* There is no good reason for a Resolution
+		 * Multiplier to have a count other than 1.
+		 * Ignore that case.
 		 */
-		if (rep->maxfield > 1) {
-			hid_hw_request(hid, rep, HID_REQ_GET_REPORT);
-			hid_hw_wait(hid);
-		}
+		if (report->field[i]->report_count != 1)
+			continue;
 
-		for (i = 0; i < rep->maxfield; i++) {
-			__s32 logical_max = rep->field[i]->logical_maximum;
+		for (j = 0; j < report->field[i]->maxusage; j++) {
+			usage = &report->field[i]->usage[j];
 
-			/* There is no good reason for a Resolution
-			 * Multiplier to have a count other than 1.
-			 * Ignore that case.
-			 */
-			if (rep->field[i]->report_count != 1)
+			if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER)
 				continue;
 
-			for (j = 0; j < rep->field[i]->maxusage; j++) {
-				usage = &rep->field[i]->usage[j];
+			*report->field[i]->value = value;
+			update_needed = true;
+		}
+	}
+
+	return update_needed;
+}
 
-				if (usage->hid != HID_GD_RESOLUTION_MULTIPLIER)
-					continue;
+static void hidinput_change_resolution_multipliers(struct hid_device *hid)
+{
+	struct hid_report_enum *rep_enum;
+	struct hid_report *rep;
+	int ret;
 
-				*rep->field[i]->value = logical_max;
-				update_needed = true;
+	rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
+	list_for_each_entry(rep, &rep_enum->report_list, list) {
+		bool update_needed = __hidinput_change_resolution_multipliers(hid,
+								     rep, true);
+
+		if (update_needed) {
+			ret = __hid_request(hid, rep, HID_REQ_SET_REPORT);
+			if (ret) {
+				__hidinput_change_resolution_multipliers(hid,
+								    rep, false);
+				return;
 			}
 		}
-		if (update_needed)
-			hid_hw_request(hid, rep, HID_REQ_SET_REPORT);
 	}
 
 	/* refresh our structs */
-- 
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