> How do you think one tests for command completion? :) There does not > seem to be a general problem reading AltStatus(BSY) during a DMA > transfer. IDE driver and other well known codebases have been doing > that for decades. You use altstatus if available but you can't do so for 400nS after command issue. > I think the undefined behavior is only where the AltStatus read occurs > before the 400ns period specified by ATA... excising the AltStatus read > there (ata_sff_pause) should be fine for PIO, but problematic for MMIO > chipsets that need posted writes flushed prior to the 400ns delay. Old IDE says no such chipsets exist. Probably because their own designers would have been lynched by the in house software team ;) -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
