Date:   Sun, 19 Mar 2023 18:45:08 +0100
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     msizanoen <msizanoen@qtmlabs.xyz>
Cc:     Pali =?utf-8?B?Um9ow6Fy?= <pali@kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Hans de Goede <hdegoede@redhat.com>, stable@vger.kernel.org,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] input: alps: fix compatibility with -funsigned-char
Message-ID: <ZBdKJJ+HJaB0mdNR@zx2c4.com>
References: <20230318144206.14309-1-msizanoen@qtmlabs.xyz>
MIME-Version: 1.0
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In-Reply-To: <20230318144206.14309-1-msizanoen@qtmlabs.xyz>
Precedence: bulk

Might be wise to clean up a few other ones in that file? Or not. Up to
you:

diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c
index 989228b5a0a4..afbf67c2488a 100644
--- a/drivers/input/mouse/alps.c
+++ b/drivers/input/mouse/alps.c
@@ -852,8 +852,8 @@ static void alps_process_packet_v6(struct psmouse *psmouse)
 			x = y = z = 0;

 		/* Divide 4 since trackpoint's speed is too fast */
-		input_report_rel(dev2, REL_X, (char)x / 4);
-		input_report_rel(dev2, REL_Y, -((char)y / 4));
+		input_report_rel(dev2, REL_X, (signed char)x / 4);
+		input_report_rel(dev2, REL_Y, -((signed char)y / 4));

 		psmouse_report_standard_buttons(dev2, packet[3]);

@@ -1104,8 +1104,8 @@ static void alps_process_trackstick_packet_v7(struct psmouse *psmouse)
 	    ((packet[3] & 0x20) << 1);
 	z = (packet[5] & 0x3f) | ((packet[3] & 0x80) >> 1);

-	input_report_rel(dev2, REL_X, (char)x);
-	input_report_rel(dev2, REL_Y, -((char)y));
+	input_report_rel(dev2, REL_X, (signed char)x);
+	input_report_rel(dev2, REL_Y, -((signed char)y));
 	input_report_abs(dev2, ABS_PRESSURE, z);

 	psmouse_report_standard_buttons(dev2, packet[1]);
diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c
index 5f0d75a45c80..43a1116c5852 100644
--- a/drivers/input/mouse/elan_i2c_core.c
+++ b/drivers/input/mouse/elan_i2c_core.c
@@ -382,7 +382,7 @@ static unsigned int elan_convert_resolution(u8 val, u8 pattern)
 	 *	((value from firmware) + 3) * 100 = dpi
 	 */
 	int res = pattern <= 0x01 ?
-		(int)(char)val * 10 + 790 : ((int)(char)val + 3) * 100;
+		(int)(signed char)val * 10 + 790 : ((int)(signed char)val + 3) * 100;
 	/*
 	 * We also have to convert dpi to dots/mm (*10/254 to avoid floating
 	 * point).