* methods; erase() is optional. set_gain() and set_autocenter() need
* only be implemented if driver sets up FF_GAIN and FF_AUTOCENTER
* bits.
+ *
+ * Note that playback(), set_gain() and set_autocenter() are called with
+ * dev->event_lock spinlock held and interrupts off and thus may not
+ * sleep.
*/
struct ff_device {
int (*upload)(struct input_dev *dev, struct ff_effect *effect,