From: Tejun Heo <htejun@gmail.com>
To: Jaychander T <jaychander@gmail.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: Reg. SATA II NCQ
Date: Mon, 22 Jan 2007 14:59:44 +0900 [thread overview]
Message-ID: <45B452D0.8030704@gmail.com> (raw)
In-Reply-To: <e93ba0ce0701170058x30a7c31cr2ce291d3f8f89080@mail.gmail.com>
Jaychander T wrote:
> I understand from the SATA II NCQ specs that for NCQ commands(FPDMA)
> we need not have to setup the DMA (PRD) for the commands issued but
> has to do
That's different thing. NCQ protocol doesn't require DMA SETUP FIS
which is required for normal DMA commands but the controller still needs
to be prepped with DMA table to know from/to where transfer data.
> so only on reception of DMA setup FIS from the drive(throught ISR).
> But in libata/ ata_qc_issue does qc prep and issue irrespective of the
> protocol.
Yeap, DMA table needs to be prepped whether NCQ is used or not.
> Even i glanced thro' the sil24 driver and seems to be the same.
The same for sil24.
--
tejun
next prev parent reply other threads:[~2007-01-22 6:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-17 8:58 Reg. SATA II NCQ Jaychander T
2007-01-22 5:59 ` Tejun Heo [this message]
2007-01-25 6:16 ` Jaychander T
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