From: Jens Axboe <axboe@suse.de>
To: Tejun Heo <htejun@gmail.com>
Cc: "zhao, forrest" <forrest.zhao@intel.com>,
Jeff Garzik <jgarzik@pobox.com>,
linux-ide@vger.kernel.org
Subject: Re: [RFC] AHCI Command Completion Coalescing(CCC) proposal
Date: Fri, 9 Jun 2006 13:49:16 +0200 [thread overview]
Message-ID: <20060609114916.GF31913@suse.de> (raw)
In-Reply-To: <44890602.90002@gmail.com>
On Fri, Jun 09 2006, Tejun Heo wrote:
> zhao, forrest wrote:
> >On Fri, 2006-06-09 at 12:47 +0900, Tejun Heo wrote:
> >>If we're gonna do it. EH needs only a few changes probably during
> >>autopsy and report. Fixing up command issue path and implementing
> >>command exclusion (NCQ vs. non-NCQ, sil24 does it in hardware, ahci
> >>doesn't) will be a bit complex though.
> >
> >Would you please elaborate on command exclusion? Why NCQ commands need
> >to be excluded from non-NCQ commands?
>
> AHCI spec rev 1.1, sect 1.7. The last paragraph says.
>
> "This multiple-use of the command list is achieved by the HBA only
> moving its command list pointer when the BSY, DRQ, and ERR bits are
> cleared by the device. System software is responsible to ensure that
> queued and non-queued commands are not mixed in the command list."
This, btw, was also the case with the legacy TCQ.
--
Jens Axboe
next prev parent reply other threads:[~2006-06-09 11:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-08 7:30 [RFC] AHCI Command Completion Coalescing(CCC) proposal zhao, forrest
2006-06-08 15:01 ` Jeff Garzik
2006-06-09 2:27 ` zhao, forrest
2006-06-09 3:11 ` Another project for you... :) Jeff Garzik
2006-06-09 3:13 ` zhao, forrest
2006-06-09 22:29 ` Greg Freemyer
2006-06-09 23:44 ` Alan Cox
2006-06-09 3:43 ` [RFC] ATA host-protected area (HPA) device mapper? Jeff Garzik
2006-06-09 4:51 ` Matthew Frost
2006-06-14 8:01 ` Another project for you... :) zhao, forrest
2006-06-14 15:19 ` Randy.Dunlap
2006-06-15 7:59 ` zhao, forrest
2006-06-15 11:47 ` Jeff Garzik
2006-06-09 3:30 ` [RFC] AHCI Command Completion Coalescing(CCC) proposal Jeff Garzik
2006-06-09 3:39 ` zhao, forrest
2006-06-09 3:43 ` Tejun Heo
2006-06-09 3:47 ` Tejun Heo
2006-06-09 3:51 ` zhao, forrest
2006-06-09 4:12 ` Jeff Garzik
2006-06-09 5:24 ` Tejun Heo
2006-06-09 11:49 ` Jens Axboe [this message]
2006-06-09 3:53 ` Jeff Garzik
2006-06-09 3:52 ` Jeff Garzik
2006-06-09 11:49 ` Jens Axboe
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