IER
error->ier = I915_READ16(IER);
error->ier = I915_READ(IER);
I915_WRITE(type##IER, 0); \
I915_WRITE16(type##IER, 0); \
I915_WRITE(type##IER, (ier_val)); \
I915_WRITE16(type##IER, (ier_val)); \