intel_dsb_head
head = intel_dsb_head(sub_dsb);
intel_dsb_head(chained_dsb));
intel_dsb_head(dsb));
unsigned int intel_dsb_head(struct intel_dsb *dsb);
intel_flipq_write(display, flipq, intel_dsb_head(dsb), i++);
intel_flipq_write(display, flipq, intel_dsb_head(dsb), i++);
intel_flipq_write(display, flipq, intel_dsb_head(dsb), i++);
intel_flipq_write(display, flipq, intel_dsb_head(dsb), i++);