From: Stephen Boyd <swboyd@chromium.org>
To: Doug Anderson <dianders@chromium.org>,
Jonathan Cameron <jic23@kernel.org>
Cc: Alexandru Ardelean <alexandru.ardelean@analog.com>,
Daniel Campello <campello@chromium.org>,
Enrico Granata <egranata@chromium.org>,
Hartmut Knaack <knaack.h@gmx.de>,
Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
linux-iio <linux-iio@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Dmitry Torokhov <dtor@chromium.org>
Subject: Re: [PATCH] iio: sx9310: Prefer async probe
Date: Tue, 01 Sep 2020 00:03:55 -0700 [thread overview]
Message-ID: <159894383586.334488.2938301456606601581@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <CAD=FV=VWrXwDwoxBK9y2ZeFEoG-edO4WktdSW0MFZLfbcS2hLQ@mail.gmail.com>
Quoting Doug Anderson (2020-08-31 11:59:37)
> On Sat, Aug 29, 2020 at 10:18 AM Jonathan Cameron <jic23@kernel.org> wrote:
> > Agreed. However, I'd like a comment next to the place we turn it on
> > saying what delays we are trying to mitigate by enabling it in this
> > driver.
>
> OK, I used function graph to get a trace. Some of the time is simply
> i2c transfers, which we do A LOT of during initialization (and i2c
> transfers aren't known for being instant). However, that's not the
> big problem. Check out the regmap_read_poll_timeout() in
> sx9310_init_compensation(). 20 ms per sleep with a 2 second timeout.
> This seems to eat over around 220 ms of the time on my system.
>
> So how do you want to do this? Do you want me to re-post the patch
> and mention the regmap_read_poll_timeout() in the commit message? Do
> you want to just add that to the commit message yourself?
>
I think the suggestion is to put a comment next to the
PROBE_PREFER_ASYNCHRONOUS flag indicating that
sx9310_init_compensation() can take a while. Should the compensation be
delayed even further though to some time when userspace opens the device
node?
next prev parent reply other threads:[~2020-09-01 7:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-29 0:01 [PATCH] iio: sx9310: Prefer async probe Douglas Anderson
2020-08-29 15:12 ` Jonathan Cameron
2020-08-29 16:56 ` Doug Anderson
2020-08-29 17:17 ` Jonathan Cameron
2020-08-31 18:59 ` Doug Anderson
2020-09-01 7:03 ` Stephen Boyd [this message]
2020-09-01 13:45 ` Jonathan Cameron
2020-09-01 15:23 ` Doug Anderson
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