void it821x_dma_start (ide_drive_t * drive);
The IT821x has a single timing register for MWDMA and for PIO operations. As we flip back and forth we have to reload the clock. In addition the rev 0x10 device only works if the same timing value is loaded into the master and slave UDMA clock so we must also reload that.
we could figure out in advance if we need to do reloads