From: Leo L. Schwab ewhac@ewhac.org
commit bc7ec91718c49d938849697cfad98fcd9877cc26 upstream.
The spaceball.c module was not properly parsing the movement reports coming from the device. The code read axis data as signed 16-bit little-endian values starting at offset 2.
In fact, axis data in Spaceball movement reports are signed 16-bit big-endian values starting at offset 3. This was determined first by visually inspecting the data packets, and later verified by consulting: http://spacemice.org/pdf/SpaceBall_2003-3003_Protocol.pdf
If this ever worked properly, it was in the time before Git...
Signed-off-by: Leo L. Schwab ewhac@ewhac.org Link: https://lore.kernel.org/r/20211221101630.1146385-1-ewhac@ewhac.org Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/input/joystick/spaceball.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
--- a/drivers/input/joystick/spaceball.c +++ b/drivers/input/joystick/spaceball.c @@ -31,6 +31,7 @@ #include <linux/module.h> #include <linux/input.h> #include <linux/serio.h> +#include <asm/unaligned.h>
#define DRIVER_DESC "SpaceTec SpaceBall 2003/3003/4000 FLX driver"
@@ -87,9 +88,15 @@ static void spaceball_process_packet(str
case 'D': /* Ball data */ if (spaceball->idx != 15) return; - for (i = 0; i < 6; i++) + /* + * Skip first three bytes; read six axes worth of data. + * Axis values are signed 16-bit big-endian. + */ + data += 3; + for (i = 0; i < ARRAY_SIZE(spaceball_axes); i++) { input_report_abs(dev, spaceball_axes[i], - (__s16)((data[2 * i + 3] << 8) | data[2 * i + 2])); + (__s16)get_unaligned_be16(&data[i * 2])); + } break;
case 'K': /* Button data */