From: Tejun Heo <htejun@gmail.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: jgarzik@pobox.com, linux-ide@vger.kernel.org, akpm@osdl.org,
torvalds@osdl.org
Subject: Re: Libata disk corruptor paths ?
Date: Wed, 11 Apr 2007 18:14:02 +0900 [thread overview]
Message-ID: <461CA6DA.4060404@gmail.com> (raw)
In-Reply-To: <20070330151525.63a5931e@the-village.bc.nu>
Alan Cox wrote:
> Found these by inspection:
>
> Command issuing goes via ata_qc_reinit() which sets up the device bits
> for the command to include the device select bit.
>
> If we are using NCQ then the code in ata_build_rw_tf sets bit 6 directly
> without using |= which clears the device select bit and means any NCQ
> command will go to the first device regardless.
>
> The non NCQ path thankfully doesn't blat the other bits and right now we
> have no slave devices on NCQ supporting hardware I believe.
The code is actually intended that way. The NCQ spec mandates the bit
to be zero. The device/head register layout is..
FUA 1 Res 0 Res Res Res Res
We probably need better comment there tho.
--
tejun
prev parent reply other threads:[~2007-04-11 9:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-30 14:15 Libata disk corruptor paths ? Alan Cox
2007-03-30 14:16 ` Alan Cox
2007-04-11 9:14 ` Tejun Heo [this message]
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=461CA6DA.4060404@gmail.com \
--to=htejun@gmail.com \
--cc=akpm@osdl.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=jgarzik@pobox.com \
--cc=linux-ide@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.