All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: Stuart MENEFY <stuart.menefy@st.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: [PATCH] libata: Keep shadow last_ctl up to date during resets
Date: Wed, 11 Mar 2009 16:42:57 +0900	[thread overview]
Message-ID: <49B76B81.9000407@kernel.org> (raw)
In-Reply-To: <49B65125.7030201@st.com>

Hello,

Stuart MENEFY wrote:
> libata keeps a shadow copy of the ATA CTL register (which is write only),
> and only writes to the hardware when the required value doesn't match
> the shadow. However this copy wasn't being maintained when performing
> reset functions. This could cause problems for the first operation after
> a reset when the correct value might not be written to the CTL register.
> 
> This problem was observed when hotplugging a drive: the identify command
> was being issued with interrupts enabled, when they should have been
> disabled.
> 
> Signed-off-by: Stuart Menefy <stuart.menefy@st.com>

Nice catch.  Maybe a nice addition would be a ata_sff_write_to_ctl()
or something which always does the right thing.

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

  reply	other threads:[~2009-03-11  7:42 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-10 11:38 [PATCH] libata: Keep shadow last_ctl up to date during resets Stuart MENEFY
2009-03-11  7:42 ` Tejun Heo [this message]
2009-03-11 12:28   ` Mark Lord
2009-03-11 13:11     ` Tejun Heo
2009-03-13 18:58 ` Jeff Garzik

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=49B76B81.9000407@kernel.org \
    --to=tj@kernel.org \
    --cc=linux-ide@vger.kernel.org \
    --cc=stuart.menefy@st.com \
    /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.