Re: something strange in libata-core.c for kernel 2.6.22-rc3

[Robert Hancock <hancockr@shaw.ca>]

Tejun Heo wrote:
> l.genoni@oltrelinux.com wrote:
>> Mybe I am wrong, but if you are detecting 40-wire cable to set them to
>> DMA/33, why the check includes also 80-wire cables configuring them to
>> DMA/33 too?
>>
>> With this patch my nvidia4 IDE controllers detects correctly and
>> configure correctly DMA/100 for my HD and DMA/33 for my DVD (the first
>> uses a 80-wire cable, the second a 40-wire cable).
>>
>> Am I wrong somewhere?
> 
> That's the drive side verification of 80c cable check, so if the
> condition triggers we downgrade 80c or unknown to 40c.  Cable detection
> on nvidia PATA is a disaster.  You're supposed to do some ACPI dancing
> and drive side detection is completely bogus.  Eeeek....
> 
> Alan, did you have a chance to test the ACPI cable detection?  It just
> didn't work when I tried it.  It always returned 80c on my machine.

Hopefully when we get that support in and working it will solve a lot of 
these issues (and others, like the laptops that have a short 40-wire 
cable that is good for high UDMA speeds which we presently have to 
hard-code detection for specific models).

-- 
Robert Hancock      Saskatoon, SK, Canada
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