Re: [SeaBIOS] [coreboot] Add IDE_TO_AHCI config

[Chuang, Alex]

Hi Scott,

Yes, the purpose is to gain the benefits of OS use of AHCI interface.
And I met the same problem when I enabled the config AHCI.
I will try to add your AHCI patch code in my side, but please kindly send the final ahci.c to me.

Best regards,
Alex

-----Original Message-----
From: Scott Duplichan [mailto:[e-mail]] 
Sent: Friday, May 27, 2011 2:44 PM
To: Chuang, Alex; [e-mail]
Subject: RE: [SeaBIOS] [coreboot] Add IDE_TO_AHCI config

Alex Chuang wrote:

]Hi,
]
]I add one config 'IDE_TO_AHCI' in 'seabios\src\Kconfig' and modify
]'seabios\src\ata.c'. Please help me to review and check-in.
]
]This 'IDE_TO_AHCI' function can let SeaBIOS handle AHCI controller as IDE
]controller when 'ATA' enable, and also let Windows OS to load AHCI inbox
]driver or chipset vender's AHCI driver. In other words, it means that SATA
]Hard Disk ran as IDE mode in SeaBIOS but AHCI mode in Windows OS.

Hello Alex,

Thanks for this contribution. Also thanks for explaining IDE_TO_AHCI.
I have seen it in BIOS setup before, but without explanation.

Before diving into the details of this change, what benefit can be
expected from using it? I assume its purpose is to gain the benefits
of OS use of AHCI interface while avoiding the need for an AHCI option
ROM. Avoiding option ROMs is certainly a good thing. But why not use AHCI
mode for both SeaBIOS and OS? SeaBIOS AHCI support works on AMD hardware
when this patch is used:
http://comments.gmane.org/gmane.comp.bios.coreboot.seabios/1663

]   if ((! CONFIG_IDE_TO_AHCI) || (pci_config_readw(bdf, PCI_CLASS_DEVICE)
]!= 0x0106))  <- New add.

You could improve readability by replacing 0x0106 with
PCI_CLASS_STORAGE_SATA.

Thanks,
Scott