From: Jonathan Cameron <jic23@kernel.org>
To: Martin Kepplinger <martink@posteo.de>,
knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net
Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] iio: mma8452: use runtime pm instead of device specific autosleep
Date: Tue, 15 Mar 2016 22:07:25 +0000 [thread overview]
Message-ID: <56E8879D.4050409@kernel.org> (raw)
In-Reply-To: <1457954789-4885-2-git-send-email-martink@posteo.de>
On 14/03/16 11:26, Martin Kepplinger wrote:
> What is this autosleep?
> -----------------------
> It slows down the device after x seconds of inactivity. The thing is, we have
> really achieved almost the same by runtime pm.
>
> differnces are:
>
> autosleep
> * uses more power during inactivity
> * the first read after inactivity slightly faster
> * complicated to understand for the user
> * no documented sysfs interface (afaik)
> * complicated to read and maintain
>
> runtime pm
> * already merged in mma8452
> * uses less power during inactivity
> * first read after inactivity slower
> * easy to use. well documented.
> * easy to maintain and understand
>
> The two approaches solve the same problem. runtime pm has more advantages
> than autosleep and comes quite close to it's behaviour anyways. As I see it,
> autosleep, even if somehow supported, would never be used anyways.
>
> So resolve this issue by "ignoring" autosleep.
>
> Signed-off-by: Martin Kepplinger <martink@posteo.de>
> Reviewed-by: Martina Kepplinger <martina.novakovic@zoho.com>
A good detailed explanation + to be cynical, if anyone actually wants to implement
it and provide numbers showing it is the best thing since sliced bread - the absence
of a comment about it not being done isn't going to stop them!
Applied, thanks,
Jonathan
> ---
> drivers/iio/accel/mma8452.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> index d0eeba0..375e45f 100644
> --- a/drivers/iio/accel/mma8452.c
> +++ b/drivers/iio/accel/mma8452.c
> @@ -17,7 +17,7 @@
> *
> * 7-bit I2C slave address 0x1c/0x1d (pin selectable)
> *
> - * TODO: orientation events, autosleep
> + * TODO: orientation events
> */
>
> #include <linux/module.h>
>
next prev parent reply other threads:[~2016-03-15 22:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-14 11:26 [PATCH 1/2] iio: mma8452: add i2c_device_id for mma8451 Martin Kepplinger
2016-03-14 11:26 ` [PATCH 2/2] iio: mma8452: use runtime pm instead of device specific autosleep Martin Kepplinger
2016-03-15 22:07 ` Jonathan Cameron [this message]
2016-03-14 11:33 ` [PATCH 1/2] iio: mma8452: add i2c_device_id for mma8451 Martin Kepplinger
2016-03-15 22:05 ` Jonathan Cameron
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