Linux-IIO Archive on lore.kernel.org
 help / color / Atom feed
From: Jonathan Cameron <jic23@kernel.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: "Mike Looijmans" <mike.looijmans@topic.nl>,
	linux-iio <linux-iio@vger.kernel.org>,
	"Dan Robertson" <dan@dlrobertson.com>,
	"Gaëtan André" <rvlander@gaetanandre.eu>,
	"Jonathan Bakker" <xc-racer2@live.ca>,
	"Lars-Peter Clausen" <lars@metafoo.de>,
	"Peter Meerwald-Stadler" <pmeerw@pmeerw.net>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 2/2] iio: accel: Add support for the Bosch-Sensortec BMI088
Date: Sun, 24 Jan 2021 13:23:44 +0000
Message-ID: <20210124132344.7181bd06@archlinux> (raw)
In-Reply-To: <CACRpkdZTJbAFK0j8U84pyW6za-SGJqGWnvertj8sXxc8Ou8VeA@mail.gmail.com>

On Sun, 24 Jan 2021 00:21:13 +0100
Linus Walleij <linus.walleij@linaro.org> wrote:

> On Sat, Jan 23, 2021 at 4:35 PM Jonathan Cameron <jic23@kernel.org> wrote:
> > [Me]  
> > > Next, I think it is better to let suspend/resume, i.e. system PM
> > > reuse runtime PM since you're implementing that. This is why
> > > we invented PM runtime force resume and force suspend.  
> >
> > Here the driver is turning more off for full suspend than in the
> > runtime path.  If that results in significant extra delay then
> > it's not appropriate to have that in the runtime suspend path.  
> 
> I see the point.
> 
> The resume path calls bmi088_accel_enable() which incurs
> a 5ms delay.
> 
> The runtime resume path incurs a 1 ms delay.
> 
> The runtime autosuspend kicks in after 2 ms.
> 
> > Maybe the simplification of not doing the deeper power saving
> > mode is worth the extra power cost or extra delay, but
> > I'm not yet convinced.  
> 
> I would personally set the autosuspend to ~20ms and just use
> one path and take a hit of 5 ms whenever we go down between
> measures if it is a system that is for human interaction, but for
> control systems this more complex set-up may be better for
> response latencies.
> 
> The current approach may be better tuned to perfection and
> we are all perfectionists :D
> 
> I'm just worrying a little about bugs and maintainability.
Fully understood.  Though for things like this I like to leave
it at the discretion of the driver author as fairly safe they
are a user of the device.  

May well make sense to go with the longer times as you
suggest though!  Over to you Mike :)

Jonathan

> 
> Yours,
> Linus Walleij


  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-19 12:46 [PATCH v6 1/2] dt-bindings: iio: accel: Add bmi088 accelerometer bindings Mike Looijmans
2021-01-19 12:46 ` [PATCH v6 2/2] iio: accel: Add support for the Bosch-Sensortec BMI088 Mike Looijmans
2021-01-20 10:09   ` kernel test robot
2021-01-20 20:22   ` Jonathan Cameron
     [not found]     ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.c4ec3c42-7acb-4ce8-997f-adf405d31335@emailsignatures365.codetwo.com>
     [not found]       ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.0d2bd5fa-15cc-4b27-b94e-83614f9e5b38.ca49b241-105e-4dde-a295-e8168cb6d390@emailsignatures365.codetwo.com>
2021-01-21  9:02         ` Mike Looijmans
2021-01-22 22:38   ` Linus Walleij
2021-01-23 15:35     ` Jonathan Cameron
2021-01-23 23:21       ` Linus Walleij
2021-01-24 13:23         ` Jonathan Cameron [this message]
     [not found]           ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.e23f1b65-3084-4bd7-abd5-c186f8c4c35c@emailsignatures365.codetwo.com>
     [not found]             ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.0d2bd5fa-15cc-4b27-b94e-83614f9e5b38.4d211e5c-af1f-4f0a-9714-ec208ef9be8d@emailsignatures365.codetwo.com>
2021-01-25  7:59               ` Mike Looijmans
2021-01-19 23:28 ` [PATCH v6 1/2] dt-bindings: iio: accel: Add bmi088 accelerometer bindings Rob Herring
2021-01-20  1:31 ` Rob Herring
     [not found]   ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.06120990-9bfb-4196-a6ce-19c5b16aae9a@emailsignatures365.codetwo.com>
     [not found]     ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.0d2bd5fa-15cc-4b27-b94e-83614f9e5b38.70d7c9ca-f015-4fc4-8136-1c0364cd5511@emailsignatures365.codetwo.com>
2021-01-20  7:21       ` Mike Looijmans
2021-01-20 18:50 ` Jonathan Cameron
     [not found]   ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.949ef384-8293-46b8-903f-40a477c056ae.c9179140-7138-467c-85e9-419e68c95bd4@emailsignatures365.codetwo.com>
     [not found]     ` <1b153bce-a66a-45ee-a5c6-963ea6fb1c82.0d2bd5fa-15cc-4b27-b94e-83614f9e5b38.02f2b6e0-f94c-4e13-b820-c0a2b10c9a96@emailsignatures365.codetwo.com>
2021-01-21  8:46       ` Mike Looijmans

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=20210124132344.7181bd06@archlinux \
    --to=jic23@kernel.org \
    --cc=dan@dlrobertson.com \
    --cc=lars@metafoo.de \
    --cc=linus.walleij@linaro.org \
    --cc=linux-iio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mike.looijmans@topic.nl \
    --cc=pmeerw@pmeerw.net \
    --cc=rvlander@gaetanandre.eu \
    --cc=xc-racer2@live.ca \
    /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-IIO Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-iio/0 linux-iio/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-iio linux-iio/ https://lore.kernel.org/linux-iio \
		linux-iio@vger.kernel.org
	public-inbox-index linux-iio

Example config snippet for mirrors

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


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