svn commit: r200432 - in stable/8: . contrib/top lib/libusb sbin/atacontrol sys/arm/mv sys/cam/ata sys/cam/scsi sys/conf sys/dev/ata sys/dev/ata/chipsets sys/powerpc/powermac sys/powerpc/psim tools...

[Alexander Motin]

Bruce Simpson wrote:
> Alexander Motin wrote:
>> Log:
>>   MFC r200171, r200182, r200275, r200295, r200359:
>>   Introduce ATA_CAM kernel option, turning ata(4) controller drivers into
>>   cam(4) interface modules. When enabled, this option deprecates all
>> ata(4)
>>   peripheral drivers (ad, acd, ...) and interfaces and allows cam(4)
>> drivers
>>   (ada, cd, ...) and interfaces to be natively used instead.
>>   
>    Does this not mean there are now two AHCI drivers? i.e. ata(4) with
> ATA_CAM, and ahci(4).

Yes, you are right: ataahci of ata(4) and ahci(4).
Same is for atasiliconimage of ata(4) and siis(4).

>    If so, which one is preferred?

ahci(4) definitely. If you load both, ahci(4) will win attachment.

ataahci give you almost no benefits of AHCI. It is only needed for some
time to support AHCI hardware in legacy mode, where it is the only
alternative. It will be dropped after ATA to CAM migration complete.

>    ahci(4) seems subjectively faster (I have not measured it),

As it should be. On some heavily parallel loads I have got almost double
speedup, while speedup of 20-30% is quite usual.

> although
> it has a minor issue on my motherboard with ATI SB700 that it does not
> turn off the HDD activity led.

I haven't seen that on my board. Describe it more in private please.

-- 
Alexander Motin