Problems with ATA_CAM support in RELENG_8

[Alexander Motin]

Paul Mather wrote:
> On Jun 30, 2010, at 5:18 PM, Alexander Motin wrote:
>> Paul Mather wrote:
>>>> PS: ATA_STATIC_ID is useless when ATA_CAM option enabled.
>>> Thank you (and Jeremy Chadwick) for the help and information.  The kernel configuration options I used above were taken from a VirtualBox FreeBSD/amd64 install I have that I converted over to ATA_CAM when the code first went into RELENG_8 and it wasn't exactly clear at the time what options were absolutely required.  (I'm not even sure that "options ATA_CAM" is needed any more, given "device ahci" implies it.)
>> `options ATA_CAM` enables CAM wrapper for legacy drivers, which gave you
>> adaX devices instead of adX. It doesn't give major benefits, just
>> unifies behavior.
> 
> So, does that mean if you omit "options ATA_CAM" and have "device ahci" you will get adX devices, not adaX devices?  In other words, if you have "device ahci" (or "device siis" or "device mvs") will you will always get adaX devices, whether or not you have "options ATA_CAM" in your kernel config file?

If you have ahci, siis and mvs drivers in kernel, but no "options
ATA_CAM", you will get adaX devices for native SATA controllers,
supported by these three drivers and adX for other (legacy) ones.

> Does "options ATA_CAM" work with "device ata" or the modular ATA subsystem? 

Both. It is an option of "device atacore", which is part of "device ata"

> Is that the intended use of "options ATA_CAM": to provide adaX devices and a CAM interface for accessing ATA devices?

Yes. It disables ATA peripheral drivers and bus management code,
allowing CAM ones to be used on top of the ATA controller drivers.

-- 
Alexander Motin