Hello, I found a bug in the sata_mv driver, that defers PIO commands indefinitely while there is a traffic on other ports of a sata port multiplier [PMP]: without traffic: time smartctl --all /dev/sdc > /dev/null real 0m0.243s with fio running and blasting read IOs on 5 drives behind the same port multiplier for 5 minutes: real 4m59.353s Obviously the PIO commands are defer while traffic is in progress. With the patch following, smart_ctl return before fio complete. It still takes 4s, time for all NCQ commands to be flushed out. real 0m4.074s Gwendal. -- 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
