Messages in this thread | | | Date | Tue, 19 Jun 2007 20:10:25 +0400 | From | Sergei Shtylyov <> | Subject | Re: [BUG] ide dma_timer_expiry, then hard lockup |
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Hello.
Linas Vepstas wrote:
>>Stuart_Hayes@Dell.com 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?
Hm... not sure about this.
>>>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.
Which makes me think this really is some *hardware* issue.
> --linas
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