From: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
To: Francesco Zanella <francesco.zanella@vimar.com>,
linux-watchdog@vger.kernel.org, wim@linux-watchdog.org,
linux@roeck-us.net
Cc: devicetree@vger.kernel.org, robh+dt@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] watchdog: gpio_wdt: add "start-at-boot" feature
Date: Fri, 23 Apr 2021 13:36:22 +0200 [thread overview]
Message-ID: <95ee0e48-2214-618a-b351-ec8d4aaf0083@prevas.dk> (raw)
In-Reply-To: <20210421162621.24910-3-francesco.zanella@vimar.com>
On 21/04/2021 18.26, Francesco Zanella wrote:
> If "start-at-boot" property is present in the device tree, start pinging
> hw watchdog at probe, in order to take advantage of kernel configs:
(1) Are you aware of the recent proposal to add a similar feature on
watchdog core level:
https://lore.kernel.org/lkml/?q=start_enable
(2) If you set always-running but not nowayout you essentially have what
you want now: If userspace opens the device [within the limit set by
OPEN_TIMEOUT if that is in effect], but then does a graceful close (i.e.
writes 'V' immediately before close()), the kernel will assume
responsibility for pinging the device. So the device isn't stopped as
such, but if you can't trust the kernel thread/timer to keep it alive,
the system is already mostly unusable. [Also, how reliable is that 'the
timer is stopped if the gpio is set to be an input' anyway].
Rasmus
next prev parent reply other threads:[~2021-04-23 11:36 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 16:26 [PATCH 0/2] GPIO WDT "start-at-boot" property Francesco Zanella
2021-04-21 16:26 ` [PATCH 1/2] dt-bindings: watchdog: gpio-wdt: add "start-at-boot" Francesco Zanella
2021-04-21 16:37 ` Guenter Roeck
2021-04-22 16:28 ` Francesco Zanella
2021-04-21 16:26 ` [PATCH 2/2] watchdog: gpio_wdt: add "start-at-boot" feature Francesco Zanella
2021-04-21 16:42 ` Guenter Roeck
2021-04-22 16:28 ` Francesco Zanella
2021-04-22 18:05 ` Guenter Roeck
2021-04-23 9:47 ` Francesco Zanella
2021-04-23 11:36 ` Rasmus Villemoes [this message]
2021-04-23 14:24 ` Francesco Zanella
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=95ee0e48-2214-618a-b351-ec8d4aaf0083@prevas.dk \
--to=rasmus.villemoes@prevas.dk \
--cc=devicetree@vger.kernel.org \
--cc=francesco.zanella@vimar.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-watchdog@vger.kernel.org \
--cc=linux@roeck-us.net \
--cc=robh+dt@kernel.org \
--cc=wim@linux-watchdog.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).