linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Wim Van Sebroeck <wim@iguana.be>
To: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Linux kernel <linux-kernel@vger.kernel.org>, linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] fix book E watchdog to take WDIOC_SETTIMEOUT arg in seconds
Date: Thu, 27 Aug 2009 22:27:09 +0200	[thread overview]
Message-ID: <20090827202709.GK29382@infomag.iguana.be> (raw)
In-Reply-To: <20090827120841.GA25303@zod.rchland.ibm.com>

Hi Josh,

> >Now we only need someone that can look at the CONFIG_4xx cases still :-)
> 
> It seems the FSL watchdog is much more flexible than the one found in 4xx
> cores.  On 4xx, you basically have 4 static choices that represent specific
> times determined by the clock frequency.  I'm concerned that the lack of
> granularity here will result in less than desirable behavior.
> 
> For example, with a 400MHz clock you would get choices of roughly:
> 
> 5.2 ms
> 83.9 ms
> 1.34 s
> 21.47 s
> 
> Personally, I consider the first two options basically unusable.  Considering
> the second two, if a user were to say "Set the timeout for 2 seconds" they
> would then get a timeout of 21 seconds with the framework Chris' patch has
> set up.  That doesn't really seem to be ideal to me.

Hmm, my opinion: in that case we should use a timer that triggers the watchdog until userspaces times out (like we do for other watchdogs allready). Maybe we should split this driver. I have the same issue with the Freescale i.mx driver that is under review also.

Kind regards,
Wim.

      reply	other threads:[~2009-08-27 20:27 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-12 18:02 [PATCH] fix book E watchdog to take WDIOC_SETTIMEOUT arg in seconds Chris Friesen
2009-08-27 11:14 ` Wim Van Sebroeck
2009-08-27 12:08   ` Josh Boyer
2009-08-27 20:27     ` Wim Van Sebroeck [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=20090827202709.GK29382@infomag.iguana.be \
    --to=wim@iguana.be \
    --cc=jwboyer@linux.vnet.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@ozlabs.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).