int drm_lock_transfer (drm_device_t * dev, __volatile__ unsigned int * lock, unsigned int context);
inside *_unlock to give lock to kernel before calling *_dma_schedule.
\param dev DRM device. \param lock lock pointer. \param context locking context. \return always one.
Resets the lock file pointer. Marks the lock as held by the given context, via the \p cmpxchg instruction.