Re: libata dev_config call order wrong.

[Brad Campbell <brad@wasp.net.au>]

Alan Cox wrote:
> On Sul, 2004-08-29 at 19:25, Jeff Garzik wrote:
> 
>>According to the Serial ATA docs, IDENTIFY DEVICE word 93 will be zero 
>>if it's Serial ATA.  Who knows if that's true, given the wierd wild 
>>world of ATA devices.
> 
> 
> You need to check if word 93 is valid first. Same with things like the
> cache control word - its value is only meaningful if the drive says the
> word is meaningful.

I'm making some assumptions here based on information I could scrape up off the net.

IDENTIFY DEVICE Word 93 support has been mandatory at least since ATA-5.

ATA-5 did not have lba48 or > udma/66.

SATA->PATA bridge boards support > udma/33 and thus must emulate an 80 conductor cable.

Thus, any device capable of lba48 (and these are the ones that trigger the > 200 sector problem) 
must (according to the ATA-5 and up standard) support correct use of the IDENTIFY DEVICE word 93 
register.

Given that the SATA->PATA bridge boards support 80 pin detection, then bit 13 of word 93 must be 
high on any drive that supports lba48, and given the *current* sata spec states that word 93 must be 
zero, we should be able to use this detection method.

Now, remember I have been an "ATA researcher" for about 4 hours now, please feel free to belt me 
with the wet salmon of enlightenment and point out the flaw in my logic. Otherwise, when I get home 
this evening I'm going to have a crack and getting this working.

Regards,
Brad