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SubjectRe: PATCH: Fix ide probe double detection
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On Thu, 29 Jul 2004 13:22:44 +1000, Benjamin Herrenschmidt wrote:
>On Wed, 2004-07-28 at 08:46, Alan Cox wrote:
>> Some devices don't decode master/slave - notably PCMCIA adapters.
>> Unfortunately for us some also do, which makes it hard to guess if we
>> should probe the slave.
>>
>> This patch fixes the problem by probing the slave and then using the model
>> and serial information to spot undecoded pairs. An additional check is done
>> to catch pairs of pre ATA devices just in case.
>
>What about checking if drive->select sticks ? And if that doesn't work,
>something like
>
>- select 0
>- write a value to reg X
>- select 1
>- write a different value to reg X
>- select 0
>- check value
>
>reg X could be nsect or such ...
>
>I don't like relying on drive->id and serial_no, but that may just be
>paranoia...
>
>Ben.

One strategy would be to reverse the order of probes, doing drive 1 first,
then drive 0. When I was working IDE in AIX, we had some ATAPI devices that
were recalcitrant until the strategy was switched to 1,0 order

++doug
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