Hi Sergei, On Tue, Jun 19, 2007 at 06:07:07PM +0400, Sergei Shtylyov wrote: > > Stuart_Hayes@xxxxxxxx wrote: > >I think reading the IDE status register clears the interrupt in the IDE > >device, which might be causing the drive to think it's OK to generate > >another interrupt. > > This is not how IDE drives are supposed to act -- they won't proceed any > further until "interrupt pending" condition is cleared, so these aren't > supposed to be "stacked". This behavior however is not strictly specified > by ATA standards IIRC, but I can't readily imagine such situaltion anyway > unless tagged command queueing (which is not supported by IDE core) and/or > ATAPI command overlapping is in action... The problem only manifests during high io load; perhaps a missing mutex somewhere is blasting one thing too many out to the hard drive? > > This could either cause it to get stuck trying to > >service an interrupt that is never getting cleared as you suggested, or > >possibly when the next IRQ comes in the IDE IRQ handler gets stuck > >waiting for a spinlock that the code you're looking at already owns...? > > I could also imagine the HPT366 chip going mad and stalling the reads if > the taskfile regs forever because of the incomplete DMA or even the drive > going mad and not replying to I/O cycles with proper -IORDY handshake (i.e. > holding it low all the time)... In my case, ctrl-alt-sysrq doesn't work, which makes it hard to debug. I'm thinking that trying to debug libata is a better idea, rather than investing time in ide, right? Although at the moment, libata works even less; see other email. --linas - 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
