linux-ide.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Mark Lord <lkml@rtr.ca>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Linus Torvalds <torvalds@osdl.org>,
	Jeff Garzik <jgarzik@pobox.com>, Conke Hu <conke.hu@amd.com>,
	linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org,
	Andrew Morton <akpm@osdl.org>
Subject: Re: AHCI should try to claim all AHCI controllers
Date: Wed, 01 Nov 2006 09:37:49 -0500	[thread overview]
Message-ID: <4548B13D.6070501@rtr.ca> (raw)
In-Reply-To: <1162383783.11965.116.camel@localhost.localdomain>

Alan Cox wrote:
> Ar Maw, 2006-10-31 am 21:22 -0800, ysgrifennodd Linus Torvalds:
>> (We had the same issue with "PCI IDE controller". Some PCI IDE controllers 
>> are clearly exactly that from a programming interface standpoint, but 
>> because they support RAID in hardware, they claim to be RAID controllers, 
>> since that is more "glamorous". Gaah ;^).
> 
> Actually its far uglier than that. With one exception they don't support
> hardware raid mode, they use the RAID class tag to stop other OS drivers
> grabbing the interface or seeing it directly as un-raided software raid.

Note that a lot of the software raid controllers actually have full
hardware RAID acceleration in the chipset (single block command is automatically
remapped across several drives of a RAID 0/1/10 configuration, reducing bus
transactions and bandwidth requirements.

But they still require a driver do perform the RAID management,
and are thus not true "hardware" RAID.  But they are higher on the
food chain than total "pretend" RAID devices.

Cheers

  reply	other threads:[~2006-11-01 14:37 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-31 15:06 AHCI should try to claim all AHCI controllers Conke Hu
2006-11-01  5:07 ` Jeff Garzik
2006-11-01  5:22   ` Linus Torvalds
2006-11-01  5:35     ` Jeff Garzik
2006-11-01 12:23     ` Alan Cox
2006-11-01 14:37       ` Mark Lord [this message]
2006-11-01  5:11 ` Jeff Garzik
  -- strict thread matches above, loose matches on Subject: below --
2006-11-01 13:39 Conke Hu
2006-11-02 13:15 ` Martin Waitz

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4548B13D.6070501@rtr.ca \
    --to=lkml@rtr.ca \
    --cc=akpm@osdl.org \
    --cc=alan@lxorguk.ukuu.org.uk \
    --cc=conke.hu@amd.com \
    --cc=jgarzik@pobox.com \
    --cc=linux-ide@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=torvalds@osdl.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).