Re: SVN rev 206755 breakage

On 19 Apr 2010, at 07:30, Alexander Motin <mav_at_FreeBSD.org> wrote:

> Rui Paulo wrote:
>> On 18 Apr 2010, at 14:05, Alexander Motin wrote:
>>> Most of AHCI controllers could also work as usual PCI ATA, but not  
>>> every
>>> PCI ATA could work as AHCI. It would be nice to compare `pciconf - 
>>> lvbc`
>>> output in both working (Rui) and not working (Michael) cases.
>>
>> ahci0_at_pci0:0:31:2:    class=0x01018f card=0x72708086  
>> chip=0x27c48086 rev=0x02 hdr=0x00
>>    vendor     = 'Intel Corporation'
>>    device     = '82801GBM/GHM (ICH7-M Family) Serial ATA Storage  
>> Controller'
>>    class      = mass storage
>>    subclass   = ATA
>
>                   ^^^
> It doesn't report itself as AHCI.
>
>>    bar   [10] = type I/O Port, range 32, base 0x20d8, size  8,  
>> enabled
>>    bar   [14] = type I/O Port, range 32, base 0x20fc, size  4,  
>> enabled
>>    bar   [18] = type I/O Port, range 32, base 0x20d0, size  8,  
>> enabled
>>    bar   [1c] = type I/O Port, range 32, base 0x20f8, size  4,  
>> enabled
>>    bar   [20] = type I/O Port, range 32, base 0x2020, size 16,  
>> enabled
>>    bar   [24] = type Memory, range 32, base 0x90445000, size 1024,  
>> enabled
>
> This resource (BAR(5)) is absent on Michael's system. It is needed to
> work in AHCI mode, but not required for legacy PCI ATA. Probably some
> kind of BIOS magic in your case makes it appear in this mode with this
> chip ID.
> On ICH8 and above in non-AHCI mode BAR(5) is also present, but with
> different meaning (access to some SATA registers). So it may be
> difficult to distinguish what exactly we have there.
>
>>    cap 01[70] = powerspec 2  supports D0 D3  current D0
>>
>> BTW, Mac OS X also uses AHCI on this controller.
>
> I think Mac OS X is very special beast, which could easily be tuned  
> for
> their specific hardware.
>
> So I think either your patch should be either reverted, or somehow
> improved to check presence of BAR(5) and may be something else on  
> probe
> stage, but IMHO it's a kind of magic and I wouldn't be doing so.

Ok I'll revert it