ATA APM and NCQ support in FreeBSD atacontrol

Andrey V. Elsukov bu7cher at yandex.ru
Mon May 12 06:14:42 UTC 2008


Jeremy Chadwick wrote:
>> No. ata(4) driver currently doesn't support/use NCQ.
> 
> Thanks for this information -- I had no idea!  I'll add this to my
> Common Issues page, although it's not so much an "issue" but more so a
> feature.
> 
> I was always under the impression that AHCI included automatic support
> for negotiation and use of extensions like NCQ and TCQ:
> 
> http://en.wikipedia.org/wiki/Native_Command_Queuing
> http://www.seagate.com/content/docs/pdf/whitepaper/D2c_tech_paper_intc-stx_sata_ncq.pdf

AHCI has standart method to determine presence of NCQ support.
But FreeBSD's driver needs some code to work with NCQ.
Soren said to me that he is going to work with NCQ support
after merging PM support, but I don't know about current status.

-- 
WBR, Andrey V. Elsukov


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