EDP_PSR_ENABLE
u32 val = EDP_PSR_ENABLE;
WARN_ON(I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE);
I915_READ(EDP_PSR_CTL) & ~EDP_PSR_ENABLE);
WARN_ON(I915_READ(EDP_PSR_CTL) & EDP_PSR_ENABLE);
WARN_ON(!(val & EDP_PSR_ENABLE));
I915_WRITE(EDP_PSR_CTL, val & ~EDP_PSR_ENABLE);