linux-kernel - Re: [RESEND][PATCH v1] drm: Discard pm_runtime

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Message-ID: <CAJZ5v0i+uXsCRk7kxLb8t+96k-SOJY-wEwNvYBXTdMKWSCdR9w@mail.gmail.com>
Date: Thu, 15 Jan 2026 14:39:43 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Liviu Dudau <liviu.dudau@....com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Linux PM <linux-pm@...r.kernel.org>, imx@...ts.linux.dev, 
	LKML <linux-kernel@...r.kernel.org>, Ulf Hansson <ulf.hansson@...aro.org>, 
	Brian Norris <briannorris@...omium.org>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
	Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
	Laurent Pinchart <Laurent.pinchart@...asonboard.com>, Jonas Karlman <jonas@...boo.se>, 
	Jernej Skrabec <jernej.skrabec@...il.com>, Shawn Guo <shawnguo@...nel.org>, 
	Sascha Hauer <s.hauer@...gutronix.de>, Fabio Estevam <festevam@...il.com>, 
	Dave Stevenson <dave.stevenson@...pberrypi.com>, 
	Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>, Maíra Canal <mcanal@...lia.com>, 
	dri-devel@...ts.freedesktop.org
Subject: Re: [RESEND][PATCH v1] drm: Discard pm_runtime_put() return value

On Thu, Jan 15, 2026 at 1:20 PM Liviu Dudau <liviu.dudau@....com> wrote:
>
> On Wed, Jan 14, 2026 at 01:03:25PM +0100, Rafael J. Wysocki wrote:
> > On Thu, Jan 8, 2026 at 4:38 PM Rafael J. Wysocki <rafael@...nel.org> wrote:
> > >
> > > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > >
> > > Multiple DRM drivers use the pm_runtime_put() return value for printing
> > > debug or even error messages and all of those messages are at least
> > > somewhat misleading.
> > >
> > > Returning an error code from pm_runtime_put() merely means that it has
> > > not queued up a work item to check whether or not the device can be
> > > suspended and there are many perfectly valid situations in which that
> > > can happen, like after writing "on" to the devices' runtime PM "control"
> > > attribute in sysfs for one example.  It also happens when the kernel
> > > has been configured with CONFIG_PM unset.
> > >
> > > For this reason, modify all of those drivers to simply discard the
> > > pm_runtime_put() return value which is what they should be doing.
> > >
> > > This will facilitate a planned change of the pm_runtime_put() return
> > > type to void in the future.
> > >
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > > Acked-by: Dave Stevenson <dave.stevenson@...pberrypi.com>
> > > Acked-by: Liviu Dudau <liviu.dudau@....com>
> > > ---
> > >
> > > This patch is requisite for converting pm_runtime_put() into a void
> > > function.
> > >
> > > If you decide to pick it up, please let me know.
> > >
> > > Otherwise, an ACK or equivalent will be appreciated, but also the lack
> > > of specific criticism will be eventually regarded as consent.
> > >
> > > Originally posted here:
> > >
> > > https://lore.kernel.org/linux-pm/3045480.e9J7NaK4W3@rafael.j.wysocki/
> >
> > This is the last patch from the "discard pm_runtime_put() return
> > values" lot that has not been applied yet, AFAICS, so this is the last
> > call for objections or concerns related to it.
>
> I think you can go ahead and apply it, I don't see how the imx8 driver will
> be affected by the lack of debug messages.

Applied then, thanks!