DP_PIPE_SEL_MASK
*pipe = REG_FIELD_GET(DP_PIPE_SEL_MASK, val);
intel_dp->DP &= ~(DP_PIPE_SEL_MASK | DP_LINK_TRAIN_MASK);
#define DP_PIPE_SEL(pipe) REG_FIELD_PREP(DP_PIPE_SEL_MASK, (pipe))
(val & DP_PIPE_SEL_MASK) == DP_PIPE_SEL(PIPE_A))
val &= ~DP_PIPE_SEL_MASK;