LKML Archive on
help / color / mirror / Atom feed
From: Tony Lindgren <>
To: Johan Hovold <>
Cc: Greg Kroah-Hartman <>,
	Rob Herring <>, Sebastian Reichel <>,
	"H. Nikolaus Schaller" <>,
	Andreas Kemnade <>,
	Mark Rutland <>,
	Arnd Bergmann <>, Pavel Machek <>,,,
Subject: Re: [PATCH 1/2] serdev: add controller runtime PM support
Date: Fri, 11 May 2018 05:56:27 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <20180511080725.GE2285@localhost>

* Johan Hovold <> [180511 08:09]:
> On Thu, May 10, 2018 at 09:48:31AM -0700, Tony Lindgren wrote:
> > If this solution works for GPS then this should also work for modems
> > that might produce data. And as long as the serdev consumer driver
> > can wake up the UART with pm_runtime_get(&serdev->ctrl->dev) then
> > the out of band GPIO wake interrupts will work to. And for TX,
> > the serdev consumer driver can toggle the wake GPIO, and then call
> > pm_runtime_get(&serdev->ctrl->dev).
> I don't think any serdev driver action is needed for TX however. The
> serial driver itself would know that there's data in the write buffer
> and should manage PM itself until the buffer has been drained (which may
> never happen due to flow control).

Sure if the serial driver can manage TX wake directly. However, the
case I'm thinking needs few hundred milliseconds after toggling the
GPIO before we can even attempt to do TX. I guess what I'm saying
let's not try to stuff any "application specific" GPIO handling to
generic UART code :)

> But either way, the mechanism introduced by this patch is general enough
> that it could in principle be used also for something like that.

Yes I agree your patches should work for both cases.



  reply	other threads:[~2018-05-11 12:56 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09  9:44 Johan Hovold
2018-05-09  9:44 ` [PATCH EXAMPLE 2/2] dbg: gnss: sirf: allow aggressive controller runtime PM Johan Hovold
2018-05-10 16:48 ` [PATCH 1/2] serdev: add controller runtime PM support Tony Lindgren
2018-05-11  8:07   ` Johan Hovold
2018-05-11 12:56     ` Tony Lindgren [this message]
2018-05-11 13:12       ` Johan Hovold
2018-05-11 16:00         ` Tony Lindgren
2018-05-11 12:35 ` Sebastian Reichel

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCH 1/2] serdev: add controller runtime PM support' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

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).