Linux-Watchdog Archive on lore.kernel.org
 help / color / Atom feed
From: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
To: Guenter Roeck <linux@roeck-us.net>,
	Adam Thomson <Adam.Thomson.Opensource@diasemi.com>,
	Marco Felsch <m.felsch@pengutronix.de>
Cc: Support Opensource <Support.Opensource@diasemi.com>,
	"wim@linux-watchdog.org" <wim@linux-watchdog.org>,
	"linux-watchdog@vger.kernel.org" <linux-watchdog@vger.kernel.org>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>
Subject: RE: [PATCH] watchdog: da9062: add power management ops
Date: Mon, 2 Dec 2019 14:44:43 +0000
Message-ID: <AM5PR1001MB0994B8FDCC3C1B991433344780430@AM5PR1001MB0994.EURPRD10.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <1feb2b8e-af46-ffa9-873a-fd9b624294b9@roeck-us.net>

On 02 December 2019 13:38, Adam Thomson wrote:

> On 12/2/19 5:27 AM, Adam Thomson wrote:
> > Hi Marco,
> >
> >>> Hmmm. Wouldn't that then be a board specific fix rather than this change?
> >>> Am concerned relying on software to reenable the watchdog on resume
> could
> >> allow
> >>> for a hang scenario potentially if that code never gets to execute. Other
> >>> systems shouldn't need this fix, assuming they don't have issues at the HW
> >>> level, so this this seems like it could be making those systems less robust. If
> >>> we are to do this at the driver level, maybe this should be an option through
> DT
> >>> to help faulty systems, but I'm thinking this shouldn't be default behaviour.
> >>
> >> I don't think that we should rely on the OTP values. Those values are
> >> set by Dialog, the SoM manufacturers or by the customer itself and the
> >> time shows that this is error prone too. At least if the customer or the
> >> SoM manufacturer don't ask the Dialog Support..
> >>
> >> You're right with the (re-)enabling but there are other drivers using
> >> such an approach.. IMHO it is safer to go this way rather than trust
> >> the OTP and the PCB layout. I would rather add a dt-compatible to tell
> >> the driver to do nothing during suspend/resume e.g.:
> >>
> >>      - dlg,use-hw-pm
> >>
> >> or something. Because the user needs to validate the PCB and the OTP
> >> values.
> >
> > The thing is the DT FW is supposed to be fairly static so I would rather not
> > enforce this change on users if they adopt a kernel version with this update in.
> > I also still think it's safer if the HW does this for us. I would have hoped for
> > most designs this would be caught in early bring up where it can be rectified
> > with minimal impact, although I'm guessing that's not the case in your scenario.
> >
> 
> dla,use-sw-pm ?
> dla,hw-pm-broken ?

Yes, I'd probably opt for 'dlg,use-sw-pm' or maybe 'dlg,manual-pm' to cover it.

> 
> Guenter

  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-28 17:19 Marco Felsch
2019-11-28 17:41 ` Guenter Roeck
2019-12-02 10:04 ` Adam Thomson
2019-12-02 10:56   ` Marco Felsch
2019-12-02 11:11     ` Adam Thomson
2019-12-02 13:03       ` Marco Felsch
2019-12-02 13:27         ` Adam Thomson
2019-12-02 13:38           ` Guenter Roeck
2019-12-02 14:44             ` Marco Felsch
2019-12-02 14:44             ` Adam Thomson [this message]
2019-12-02 15:06               ` Marco Felsch
2019-12-02 15:17                 ` Adam Thomson

Reply instructions:

You may reply publically 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=AM5PR1001MB0994B8FDCC3C1B991433344780430@AM5PR1001MB0994.EURPRD10.PROD.OUTLOOK.COM \
    --to=adam.thomson.opensource@diasemi.com \
    --cc=Support.Opensource@diasemi.com \
    --cc=kernel@pengutronix.de \
    --cc=linux-watchdog@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=m.felsch@pengutronix.de \
    --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

Linux-Watchdog Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-watchdog/0 linux-watchdog/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-watchdog linux-watchdog/ https://lore.kernel.org/linux-watchdog \
		linux-watchdog@vger.kernel.org
	public-inbox-index linux-watchdog

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-watchdog


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git