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From:   Henry Castro <hcvcastro@gmail.com>
To:     thunderbird2k@gmail.com
Cc:     Henry Castro <hcvcastro@gmail.com>, Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] drivers: hid: adjust gyro calibration data
Date:   Thu,  6 Oct 2022 09:36:08 -0400
Message-Id: <20221006133609.3839-1-hcvcastro@gmail.com>
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References: <CAEc3jaDLE1_+cCdL0nwUq-TPzBhoPmukGs527TokNN=iwqO5Hw@mail.gmail.com>
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For some reason my DualShock 4 get the calibration
data values equal:

	gyro_pitch_plus == gyro_pitch_minus

Probably due to some defect in the DS4 hardware, and cause
a CPU division exception to crash the linux kernel.

At least with the patch, I can continue play Retroarch
without using the Gyroscope :)

Signed-off-by: Henry Castro <hcvcastro@gmail.com>
---

>> Hm, I'm not the biggest fan. Is this an official DS4 or a clone
>> device? It sounds like it is some type of clone (some look real).

Sorry it happens in my DS4 clone:

I have the log values:

gyro_pitch_plus = 8704
giro_pitch_minus = 8704

Then the division exception:

mult_frac(x, y, 0)


 drivers/hid/hid-sony.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
index 87b538656f64..656caa07b25f 100644
--- a/drivers/hid/hid-sony.c
+++ b/drivers/hid/hid-sony.c
@@ -1823,6 +1823,15 @@ static int dualshock4_get_calibration_data(struct sony_sc *sc)
 	acc_z_plus       = get_unaligned_le16(&buf[31]);
 	acc_z_minus      = get_unaligned_le16(&buf[33]);

+	if (gyro_pitch_plus == gyro_pitch_minus)
+		gyro_pitch_minus *= -1;
+
+	if (gyro_yaw_plus == gyro_yaw_minus)
+		gyro_yaw_minus *= -1;
+
+	if (gyro_roll_plus == gyro_roll_minus)
+		gyro_roll_minus *= -1;
+
 	/* Set gyroscope calibration and normalization parameters.
 	 * Data values will be normalized to 1/DS4_GYRO_RES_PER_DEG_S degree/s.
 	 */
--
2.20.1