linux-kernel - Re: [PATCH] drm/bridge: ti-sn65dsi86: Properly undo autosuspend

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Date:   Mon, 28 Feb 2022 09:54:36 -0800
From:   Doug Anderson <dianders@...omium.org>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Brian Norris <briannorris@...omium.org>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Jonas Karlman <jonas@...boo.se>,
        Neil Armstrong <narmstrong@...libre.com>,
        Robert Foss <robert.foss@...aro.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/bridge: ti-sn65dsi86: Properly undo autosuspend

Hi,

On Wed, Feb 23, 2022 at 7:55 AM Laurent Pinchart
<laurent.pinchart@...asonboard.com> wrote:
>
> Hi Doug,
>
> On Wed, Feb 23, 2022 at 07:43:27AM -0800, Doug Anderson wrote:
> > On Tue, Feb 22, 2022 at 9:08 PM Laurent Pinchart wrote:
> > > On Tue, Feb 22, 2022 at 11:44:54PM +0100, Linus Walleij wrote:
> > > > On Tue, Feb 22, 2022 at 11:19 PM Douglas Anderson wrote:
> > > > >
> > > > > The PM Runtime docs say:
> > > > >   Drivers in ->remove() callback should undo the runtime PM changes done
> > > > >   in ->probe(). Usually this means calling pm_runtime_disable(),
> > > > >   pm_runtime_dont_use_autosuspend() etc.
> > > > >
> > > > > We weren't doing that for autosuspend. Let's do it.
> > > > >
> > > > > Fixes: 9bede63127c6 ("drm/bridge: ti-sn65dsi86: Use pm_runtime autosuspend")
> > > > > Signed-off-by: Douglas Anderson <dianders@...omium.org>
> > > >
> > > > Hm. I know a few places in drivers where I don't do this :/
> > >
> > > It seems to be a very common problem indeed, I haven't seen any driver
> > > yet that uses pm_runtime_dont_use_autosuspend(). We could play a game of
> > > whack-a-mole, but we'll never win. Could this be solved in the runtime
> > > PM framework instead ? pm_runtime_disable() could disable auto-suspend.
> > > If there are legitimate use cases for disabling runtime PM temporarily
> > > without disabling auto-suspend, then a new function designed
> > > specifically for remove() that would take care of cleaning everything up
> > > could be another option.
> >
> > Yeah, it would be good. It's probably not a yak I have time to shave
> > right now, though. :(
>
> I don't insist on shaving that yak right now :-) This patch is fine.

Landed in drm-misc-fixes:

26d347434829 drm/bridge: ti-sn65dsi86: Properly undo autosuspend

-Doug