Alan Cox wrote: >> * Albert: irq_on/off. Really need to give this some thought. Not sure >> I like where this model is going. Polling and twiddling irq on/off >> should be kept to a minimum, because it's sorta an admission that the >> host state machine has broken down, and we need to bandaid. Its a >> bandaid not a root-cause solution. > > I think of it more as an admission that the IDE design is lacking in a > few areas. No suprise as its an emulation of a 15 year old interface that > was normally used polled.
I second Alan's opinion. The root cause of the problem is that the controller lacks reliable IRQ masking and pending register. If you add a slightly malfunctioning controller and/or device into the mix, it's guaranteed to break. And there's another addition to the mess from SATA land which I discovered a few days ago. Some SATA controllers with SFF interface don't send non-command H2D Reg FIS when ATA_NIEN is toggled, so the updated ATA_NIEN is sent together with the next command && some SATA devices don't honor ATA_NIEN on command H2D Reg FIS. Fun! I think we should go combined IRQ + polling mode Jeff once mentioned so that we automatically fallback to polling if IRQ doesn't work for some reason. To do that, we need reliable IRQ masking && the only way to achieve proper IRQ masking on SFF controllers seems plugging it from the host side. Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
