ahci issue on MCP89 with Macbookpro7,1

[Panard <panard@backzone.net>]

Dear all,

it seems that the ahci drivers fails with the (apparently supported) MCP89 
chipset on Macbookpro7,1 machines.

Typical error messages are :
[   12.520091] ata2: COMRESET failed (errno=-16)
[   12.520102] ata1: COMRESET failed (errno=-16)
[   17.910090] ata2: link is slow to respond, please be patient (ready=0)
[   17.910095] ata1: link is slow to respond, please be patient (ready=0)
[   22.530090] ata2: COMRESET failed (errno=-16)
[   22.530097] ata1: COMRESET failed (errno=-16)
[   27.920090] ata1: link is slow to respond, please be patient (ready=0)
[   27.920094] ata2: link is slow to respond, please be patient (ready=0)
[   57.560090] ata1: COMRESET failed (errno=-16)
[   57.560095] ata1: limiting SATA link speed to 1.5 Gbps
[   57.560102] ata2: COMRESET failed (errno=-16)
[   57.560105] ata2: limiting SATA link speed to 1.5 Gbps
[   62.590090] ata1: COMRESET failed (errno=-16)
[   62.590094] ata1: reset failed, giving up
[   62.590105] ata2: COMRESET failed (errno=-16)
[   62.590108] ata2: reset failed, giving up

Hence, no disk nor cdrom work on macbookpro7,1.
Full dmesgs, etc. can be found at 
https://bugzilla.kernel.org/show_bug.cgi?id=15923 .

I wonder if there may be any parameters to tune in kernel command line to 
overcome this issue? Or is this a strong issue with the current driver?

I can provide supplementary debug messages if needed.

Thanks,

Panard