Linux-ARM-Kernel Archive on lore.kernel.org
 help / color / Atom feed
From: Tomasz Figa <tfiga@chromium.org>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: devicetree@vger.kernel.org,
	"Eddie Cai" <eddie.cai.linux@gmail.com>,
	kernel@collabora.com, "Heiko Stübner" <heiko@sntech.de>,
	"Chen Jacob" <jacob2.chen@rock-chips.com>,
	Jeffy <jeffy.chen@rock-chips.com>, 钟以崇 <zyc@rock-chips.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Allon Huang" <allon.huang@rock-chips.com>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>,
	"Helen Koike" <helen.koike@collabora.com>,
	"Jacob Chen" <cc@rock-chips.com>,
	"Hans Verkuil" <hans.verkuil@cisco.com>,
	"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>,
	"Shunqian Zheng" <zhengsq@rock-chips.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Ezequiel Garcia" <ezequiel@collabora.com>,
	"list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
	Joerg Roedel <joro@8bytes.org>,
	" <linux-arm-kernel@lists.infradead.org>,
	"Linux Media Mailing List" <linux-media@vger.kernel.org>
Subject: Re: [PATCH v8 05/14] media: rkisp1: add Rockchip ISP1 subdev driver
Date: Thu, 15 Aug 2019 19:29:59 +0900
Message-ID: <CAAFQd5Cd2k5ZCDfu=a281NLOa88vpm-P7ZPWF4Nnx==iyEkn7A@mail.gmail.com> (raw)
In-Reply-To: <20190815082422.GM6133@paasikivi.fi.intel.com>

On Thu, Aug 15, 2019 at 5:25 PM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> Hi Helen,
>
> On Wed, Aug 14, 2019 at 09:58:05PM -0300, Helen Koike wrote:
>
> ...
>
> > >> +static int rkisp1_isp_sd_set_fmt(struct v4l2_subdev *sd,
> > >> +                           struct v4l2_subdev_pad_config *cfg,
> > >> +                           struct v4l2_subdev_format *fmt)
> > >> +{
> > >> +  struct rkisp1_device *isp_dev = sd_to_isp_dev(sd);
> > >> +  struct rkisp1_isp_subdev *isp_sd = &isp_dev->isp_sdev;
> > >> +  struct v4l2_mbus_framefmt *mf = &fmt->format;
> > >> +
> > >
> > > Note that for sub-device nodes, the driver is itself responsible for
> > > serialising the access to its data structures.
> >
> > But looking at subdev_do_ioctl_lock(), it seems that it serializes the
> > ioctl calls for subdevs, no? Or I'm misunderstanding something (which is
> > most probably) ?
>
> Good question. I had missed this change --- subdev_do_ioctl_lock() is
> relatively new. But setting that lock is still not possible as the struct
> is allocated in the framework and the device is registered before the
> driver gets hold of it. It's a good idea to provide the same serialisation
> for subdevs as well.
>
> I'll get back to this later.
>
> ...
>
> > >> +static int rkisp1_isp_sd_s_power(struct v4l2_subdev *sd, int on)
> > >
> > > If you support runtime PM, you shouldn't implement the s_power op.
> >
> > Is is ok to completly remove the usage of runtime PM then?
> > Like this http://ix.io/1RJb ?
>
> Please use runtime PM instead. In the long run we should get rid of the
> s_power op. Drivers themselves know better when the hardware they control
> should be powered on or off.
>

One also needs to use runtime PM to handle power domains and power
dependencies on auxiliary devices, e.g. IOMMU.

> >
> > tbh I'm not that familar with runtime PM and I'm not sure what is the
> > difference of it and using s_power op (and Documentation/power/runtime_pm.rst
> > is not being that helpful tbh).
>
> You can find a simple example e.g. in
> drivers/media/platform/atmel/atmel-isi.c .
>
> >
> > >
> > > You'll still need to call s_power on external subdevs though.
> > >
> > >> +{
> > >> +  struct rkisp1_device *isp_dev = sd_to_isp_dev(sd);
> > >> +  int ret;
> > >> +
> > >> +  v4l2_dbg(1, rkisp1_debug, &isp_dev->v4l2_dev, "s_power: %d\n", on);
> > >> +
> > >> +  if (on) {
> > >> +          ret = pm_runtime_get_sync(isp_dev->dev);
> >
> > If this is not ok to remove suport for runtime PM, then where should I put
> > the call to pm_runtime_get_sync() if not in this s_power op ?
>
> Basically the runtime_resume and runtime_suspend callbacks are where the
> device power state changes are implemented, and pm_runtime_get_sync and
> pm_runtime_put are how the driver controls the power state.
>
> So you no longer need the s_power() op at all. The op needs to be called on
> the pipeline however, as there are drivers that still use it.
>

For this driver, I suppose we would _get_sync() when we start
streaming (in the hardware, i.e. we want the ISP to start capturing
frames) and _put() when we stop and the driver shouldn't perform any
access to the hardware when the streaming is not active.

Best regards,
Tomasz

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply index

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-30 18:42 [PATCH v8 00/14] Rockchip ISP1 Driver Helen Koike
2019-07-30 18:42 ` [PATCH v8 01/14] media: videodev2.h, v4l2-ioctl: add rkisp1 meta buffer format Helen Koike
2019-08-15 13:30   ` Laurent Pinchart
2019-07-30 18:42 ` [PATCH v8 02/14] media: doc: add document for " Helen Koike
2019-08-07 13:09   ` Sakari Ailus
2019-08-15 13:51   ` Laurent Pinchart
2019-07-30 18:42 ` [PATCH v8 03/14] media: rkisp1: Add user space ABI definitions Helen Koike
2019-08-15 18:46   ` Laurent Pinchart
2019-07-30 18:42 ` [PATCH v8 04/14] media: rkisp1: add Rockchip MIPI Synopsys DPHY driver Helen Koike
2019-08-07 13:05   ` Sakari Ailus
2019-08-07 13:37     ` Helen Koike
2019-08-15 17:54       ` Laurent Pinchart
2019-08-15 18:26         ` Heiko Stübner
2019-08-21 21:46         ` Helen Koike
2019-08-22  2:32           ` Laurent Pinchart
2019-07-30 18:42 ` [PATCH v8 05/14] media: rkisp1: add Rockchip ISP1 subdev driver Helen Koike
2019-08-06 18:51   ` Helen Koike
2019-08-07 10:39     ` Hans Verkuil
2019-08-15 19:35       ` Laurent Pinchart
2019-08-08  9:14   ` Sakari Ailus
2019-08-15  0:58     ` Helen Koike
2019-08-15  8:24       ` Sakari Ailus
2019-08-15 10:29         ` Tomasz Figa [this message]
2019-08-15 10:45           ` Sakari Ailus
2019-08-15 13:17         ` Sakari Ailus
2019-08-16  0:13   ` Laurent Pinchart
2019-07-30 18:42 ` [PATCH v8 06/14] media: rkisp1: add ISP1 statistics driver Helen Koike
2019-08-08  9:37   ` Sakari Ailus
2019-07-30 18:42 ` [PATCH v8 07/14] media: rkisp1: add ISP1 params driver Helen Koike
2019-07-30 18:42 ` [PATCH v8 09/14] media: rkisp1: add rockchip isp1 core driver Helen Koike
2019-08-07 15:27   ` Sakari Ailus
2019-08-08 21:59     ` Helen Koike
2019-08-09 12:05       ` Sakari Ailus
2019-08-07 15:36   ` Sakari Ailus
2019-07-30 18:42 ` [PATCH v8 10/14] dt-bindings: Document the Rockchip ISP1 bindings Helen Koike
2019-08-16  0:21   ` Laurent Pinchart
2019-07-30 18:42 ` [PATCH v8 11/14] dt-bindings: Document the Rockchip MIPI RX D-PHY bindings Helen Koike
2019-08-15 18:14   ` Laurent Pinchart
2019-07-30 18:42 ` [PATCH v8 12/14] arm64: dts: rockchip: add isp0 node for rk3399 Helen Koike
2019-07-30 18:42 ` [PATCH v8 13/14] arm64: dts: rockchip: add rx0 mipi-phy " Helen Koike
2019-07-30 18:42 ` [PATCH v8 14/14] MAINTAINERS: add entry for Rockchip ISP1 driver Helen Koike
2019-08-15 13:56   ` Laurent Pinchart
2019-07-30 20:15 ` [PATCH v8 00/14] Rockchip ISP1 Driver Hans Verkuil
2019-07-30 20:50   ` Helen Koike
2019-07-31  0:08     ` Helen Koike
2019-07-31  4:29       ` Hans Verkuil
2019-07-31  4:33         ` Hans Verkuil
2019-07-31  4:55           ` Hans Verkuil
2019-07-31 14:42             ` Helen Koike
2019-08-07 15:37 ` Sakari Ailus
2019-08-07 17:57   ` Helen Koike
2019-08-09 18:45 ` Manivannan Sadhasivam

Reply instructions:

You may reply publically 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:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

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

  git send-email \
    --in-reply-to='CAAFQd5Cd2k5ZCDfu=a281NLOa88vpm-P7ZPWF4Nnx==iyEkn7A@mail.gmail.com' \
    --to=tfiga@chromium.org \
    --cc=allon.huang@rock-chips.com \
    --cc=cc@rock-chips.com \
    --cc=devicetree@vger.kernel.org \
    --cc=eddie.cai.linux@gmail.com \
    --cc=ezequiel@collabora.com \
    --cc=hans.verkuil@cisco.com \
    --cc=heiko@sntech.de \
    --cc=helen.koike@collabora.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jacob2.chen@rock-chips.com \
    --cc=jeffy.chen@rock-chips.com \
    --cc=joro@8bytes.org \
    --cc=kernel@collabora.com \
    --cc=laurent.pinchart@ideasonboard.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-rockchip@lists.infradead.org \
    --cc=mchehab@kernel.org \
    --cc=sakari.ailus@linux.intel.com \
    --cc=zhengsq@rock-chips.com \
    --cc=zyc@rock-chips.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

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

Linux-ARM-Kernel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/0 linux-arm-kernel/git/0.git
	git clone --mirror https://lore.kernel.org/linux-arm-kernel/1 linux-arm-kernel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-kernel linux-arm-kernel/ https://lore.kernel.org/linux-arm-kernel \
		linux-arm-kernel@lists.infradead.org
	public-inbox-index linux-arm-kernel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-arm-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git