From: Evgeniy Polyakov <zbr@ioremap.net>
To: Jan Weitzel <J.Weitzel@phytec.de>
Cc: Andrew Morton <akpm@google.com>,
linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC] w1: Disable irqs in critical section
Date: Wed, 14 Sep 2011 23:45:49 +0400 [thread overview]
Message-ID: <20110914194549.GA20300@ioremap.net> (raw)
In-Reply-To: <1316003005.4369.10.camel@lws-weitzel>
On Wed, Sep 14, 2011 at 02:23:25PM +0200, Jan Weitzel (J.Weitzel@phytec.de) wrote:
> > Finally, can we fine-tune the interrupt-disabled section a bit? For
> > example, can the local_irq_disable() be moved to after the
> > write_bit(..., 0)?
> >
> The falling edge from 1 to 0 starts timing for the slave. After the 6µs
> the slave should drive the line low (In case the information bit is
> "0"). So there is no additional edge on the line. If there is an
> interrupt and the low pulse from master is longer, slave did't see it.
> Master need to generate the 1 -> 0 transition and measure after 15µs
>
> I tested it anyhow. Behaviour is slightly better than without disabling
> interrupts. Only disabling it for 15µs fix the problem.
Sad story, but if it is the only solution, then we should go with it.
Andrew, please push this patch upstream.
Thank you Jan.
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
--
Evgeniy Polyakov
prev parent reply other threads:[~2011-09-14 19:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-07 8:48 [RFC] w1: Disable irqs in critical section Jan Weitzel
2011-09-07 17:50 ` Evgeniy Polyakov
2011-09-08 5:46 ` Jan Weitzel
2011-09-13 22:41 ` Andrew Morton
2011-09-14 12:23 ` Jan Weitzel
2011-09-14 19:45 ` Evgeniy Polyakov [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=20110914194549.GA20300@ioremap.net \
--to=zbr@ioremap.net \
--cc=J.Weitzel@phytec.de \
--cc=akpm@google.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.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