On Mon, 05 Nov 2007 09:05:48 +0900 Tejun Heo <htejun@xxxxxxxxx> wrote: > Alan Cox wrote: > >> Maybe we could set a limit here. If the ATAPI device keeps DRQ=1 and > >> exceeds the limit, we consider it as HSM violation and have EH handle it. > > > > On a DMA transfer its basically out of our control (and a PIO drain will > > lock some controllers solid until power cycle), > > Do such controllers lock up on PIO draining after PIO transfers too? > Can you tell which are those controllers? Promise PDC202xx will lock on a PIO drain of a DMA transfer or (if you reset it before you drain) on a PIO drain of a PIO transfer. > > but on PIO we know we > > never set a chunk size over 64K, so if we exceed 64K its time to apply a > > larger hammer > > Draining is related to the amount of data the drive responds not to the > chunk size. I agree 64k should be enough for most cases but I think > there can be corner cases where this doesn't hold. Tapes perhaps yes ? - 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
