Re: LibPATA code issues / 2.6.17.3 (What is the next step?)

[Mark Lord <liml@rtr.ca>]

Mark Lord wrote:
> Justin Piszcz wrote:
>> They are Western Digital 400* drives.
>>
>> [4294678.049000]   Vendor: ATA       Model: WDC WD4000KD-00N  Rev: 01.0
>> [4294678.050000]   Vendor: ATA       Model: WDC WD4000KD-00N  Rev: 01.0
>>
>> On a SiL controller, it also happens when they are on a promise 
>> controller too.
>>
>> On Fri, 14 Jul 2006, Mark Lord wrote:
>>
>>> Justin Piszcz wrote:
>>>>
>>>> opcode=0x35 & opcode=0xca
>>>
>>> Those are non-DMA WRITE opcodes.  Using PIO for I/O is pretty rare 
>>> these days,
>>> so I'm betting that this is not a hard disk device -- compactflash?
> 
> Okay.  So why are we issuing PIO WRITE commands to drives that
> obviously should only be sent DMA commands by libata?
> 
> Perhaps that's the bug.

Oh wait.. I remember this.. No, those are DMA commands,
despite the misleading libata name for them.  We went through
this before last spring..

Okay.  So I wonder what's really going on.
The next step would be to instrument the interrupt handler,
so that when it sees bad-status, it dumps out the stat/err values
right then and there, before anything else can muck with them.

It might also be good to have it dump out the controller engine's
DMA status/err values, assuming the controller has registers for those.

Then we should get a better picture of what's going on.
Assuming the drives aren't lying to us (a perfectly good assumption here),
then the controller must be aborting the transfer unexpectedly.

Cheers