Re: [PATCH 3/5] libata: Implement disk shock protection support

[Tejun Heo]

Alan Cox wrote:
>> However, SATA or not, there simply isn't a way to abort commands in ATA.
>>  Issuing random command while other commands are in progress simply is
>> state machine violation and there will be many interesting results
>> including complete system lockup (ATA controller dying while holding the
>> PCI bus).  The only reliable way to abort in-flight commands are by
>> issuing hardreset.  However, ATA reset protocol is not designed for
>> quick recovery.  The machine is gonna hit the ground hard way before the
>> reset protocol is complete.
> 
> Actually you cau can issue idle immediate on older ATA devices. I am not
> clear if that was stuck back into the current accelerometer friendly
> drives or not. Would need to check with IBLenovo

Was that something intentional or was it a happy accident?  There can be
bus ownership problem on PATA and on SATA this is much more state logic
on both sides of the cable and I think things like that would be more
difficult to work accidentally.

Thanks.

-- 
tejun
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