Adding support for a Dell Venue 8 Pro tablet. Rotation was off by 90° to the left initially, the proposed change fixes the issue on my device.
sensor:modalias:platform:HID-SENSOR-200073:dmi:*svnDell*:pnVostro5581:*
ACCEL_LOCATION=base
+# Dell Venue 8 Pro 3845
+sensor:modalias:acpi:INVN6500*:dmi:*svnDellInc.*:pnVenue8Pro3845*
+ ACCEL_MOUNT_MATRIX=0, -1, 0; -1, 0, 0; 0, 0, 1
+
# Dell Venue 10 Pro 5055
sensor:modalias:acpi:INVN6500*:dmi:*svnDell*:pnVenue10Pro5055*
ACCEL_MOUNT_MATRIX=0, -1, 0; 1, 0, 0; 0, 0, 1