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Message-ID: <ZxIoR6T6V0WgDdq0@tom-HP-ZBook-Fury-15-G7-Mobile-Workstation>
Date: Fri, 18 Oct 2024 11:20:07 +0200
From: Tommaso Merciai <tomm.merciai@...il.com>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: sakari.ailus@...ux.intel.com,
Mauro Carvalho Chehab <mchehab@...nel.org>,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: i2c: ov5645: add HAS_EVENTS supporty
Hi Laurent,
On Wed, Oct 16, 2024 at 11:08:36PM +0300, Laurent Pinchart wrote:
> Hi Tommaso,
>
> On Tue, Oct 15, 2024 at 06:37:58PM +0200, Tommaso Merciai wrote:
> > On Tue, Oct 15, 2024 at 08:16:13AM +0200, Tommaso Merciai wrote:
> > > On Mon, Oct 14, 2024 at 08:54:52PM +0300, Laurent Pinchart wrote:
> > > > On Mon, Oct 14, 2024 at 07:38:40PM +0200, Tommaso Merciai wrote:
> > > > > Controls can be exposed to userspace via a v4l-subdevX device, and
> > > > > userspace has to be able to subscribe to control events so that it is
> > > > > notified when the control changes value.
> > > > > Add missing HAS_EVENTS support: flag and .(un)subscribe_event().
> > > > >
> > > > > Signed-off-by: Tommaso Merciai <tomm.merciai@...il.com>
> > > > > ---
> > > > > drivers/media/i2c/ov5645.c | 10 +++++++++-
> > > > > 1 file changed, 9 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/drivers/media/i2c/ov5645.c b/drivers/media/i2c/ov5645.c
> > > > > index 0c32bd2940ec..2c5145d5c616 100644
> > > > > --- a/drivers/media/i2c/ov5645.c
> > > > > +++ b/drivers/media/i2c/ov5645.c
> > > > > @@ -29,6 +29,7 @@
> > > > > #include <linux/slab.h>
> > > > > #include <linux/types.h>
> > > > > #include <media/v4l2-ctrls.h>
> > > > > +#include <media/v4l2-event.h>
> > > > > #include <media/v4l2-fwnode.h>
> > > > > #include <media/v4l2-subdev.h>
> > > > >
> > > > > @@ -1034,6 +1035,11 @@ static const struct v4l2_subdev_video_ops ov5645_video_ops = {
> > > > > .s_stream = ov5645_s_stream,
> > > > > };
> > > > >
> > > > > +static const struct v4l2_subdev_core_ops ov5645_subdev_core_ops = {
> > > > > + .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
> > > > > + .unsubscribe_event = v4l2_event_subdev_unsubscribe,
> > > > > +};
> > > > > +
> > > > > static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> > > > > .enum_mbus_code = ov5645_enum_mbus_code,
> > > > > .enum_frame_size = ov5645_enum_frame_size,
> > > > > @@ -1043,6 +1049,7 @@ static const struct v4l2_subdev_pad_ops ov5645_subdev_pad_ops = {
> > > > > };
> > > > >
> > > > > static const struct v4l2_subdev_ops ov5645_subdev_ops = {
> > > > > + .core = &ov5645_subdev_core_ops,
> > > > > .video = &ov5645_video_ops,
> > > > > .pad = &ov5645_subdev_pad_ops,
> > > > > };
> > > > > @@ -1178,7 +1185,8 @@ static int ov5645_probe(struct i2c_client *client)
> > > > >
> > > > > v4l2_i2c_subdev_init(&ov5645->sd, client, &ov5645_subdev_ops);
> > > > > ov5645->sd.internal_ops = &ov5645_internal_ops;
> > > > > - ov5645->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> > > > > + ov5645->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> > > > > + V4L2_SUBDEV_FL_HAS_EVENTS;
> > > >
> > > > Instead of patching every subdev driver, should we handle all of this in
> > > > the subdev core ? If a control handler is set for the subdev, we could
> > > > set the HAS_EVENTS flag automatically, and default to
> > > > v4l2_ctrl_subdev_subscribe_event() and v4l2_event_subdev_unsubscribe()
> > > > if there are no control operations.
> >
> > Premit:
> > - Don't know if I'm wrong eh.
>
> Nobody knows :-)
>
> > This can be done into:
> >
> > __v4l2_subdev_init_finalize()
> >
> > Adding:
> >
> > if (sd->ctrl_handler)
> > sd->flags |= V4L2_SUBDEV_FL_HAS_EVENTS;
> >
> > And check if there are no control operations using:
> >
> > bool has_subscribe_event;
> > bool has_unsubscribe_event;
> >
> >
> > has_subscribe_event = v4l2_subdev_has_op(sd, core, subscribe_event);
> > has_unsubscribe_event = v4l2_subdev_has_op(sd, core, unsubscribe_event);
> >
> > if (!has_subscribe_event)
> > assign v4l2_ctrl_subdev_subscribe_event as default .subscribe ops(somehow)
>
> We can't change the ops structure as it's constant. Something like this
> could do:
>
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 3a4ba08810d2..41ae18a0d41e 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -691,10 +691,24 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
> return v4l2_event_dequeue(vfh, arg, file->f_flags & O_NONBLOCK);
>
> case VIDIOC_SUBSCRIBE_EVENT:
> - return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg);
> + if (v4l2_subdev_has_op(sd, core, subscribe_event))
> + return v4l2_subdev_call(sd, core, subscribe_event, vfh,
> + arg);
> + else if ((sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS) &&
> + vfh->ctrl_handler)
> + return v4l2_ctrl_subdev_subscribe_event(sd, vfh, arg);
> + else
> + return -ENOIOCTLCMD;
>
> case VIDIOC_UNSUBSCRIBE_EVENT:
> - return v4l2_subdev_call(sd, core, unsubscribe_event, vfh, arg);
> + if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
> + return -ENOIOCTLCMD;
> +
> + if (v4l2_subdev_has_op(sd, core, unsubscribe_event))
> + return v4l2_subdev_call(sd, core, unsubscribe_event,
> + vfh, arg);
> + else
+ return v4l2_event_subdev_unsubscribe(sd, vfh, arg);
Thanks for your "more than an hint :)"
I'm able to test this on ov5645:
Adding:
+++ b/drivers/media/i2c/ov5645.c
@@ -1238,6 +1238,12 @@ static int ov5645_probe(struct i2c_client *client)
ov5645_init_state(&ov5645->sd, NULL);
+ ret = v4l2_subdev_init_finalize(&ov5645->sd);
+ if (ret < 0) {
+ dev_err(dev, "subdev initialization error %d\n", ret);
+ goto err_free_state;
+ }
+
ret = v4l2_async_register_subdev(&ov5645->sd);
if (ret < 0) {
dev_err(dev, "could not register v4l2 device\n");
@@ -1251,6 +1257,8 @@ static int ov5645_probe(struct i2c_client *client)
return 0;
+err_free_state:
+ v4l2_subdev_cleanup(&ov5645->sd);
err_pm_runtime:
pm_runtime_disable(dev);
pm_runtime_put_noidle(dev);
@@ -1272,6 +1280,7 @@ static void ov5645_remove(struct i2c_client *client)
v4l2_async_unregister_subdev(&ov5645->sd);
media_entity_cleanup(&ov5645->sd.entity);
+ v4l2_subdev_cleanup(&ov5645->sd);
v4l2_ctrl_handler_free(&ov5645->ctrls);
pm_runtime_disable(ov5645->dev);
if (!pm_runtime_status_suspended(ov5645->dev))
Then from the compliance tool I'm getting now good results:
Total for device /dev/v4l-subdev1: 44, Succeeded: 44, Failed: 0, Warnings: 0
I will send these 2 patches later if you agree (1 v4l2-subdev 1 ov5645.c)
Thanks again.
Regards,
Tommaso
>
> #ifdef CONFIG_VIDEO_ADV_DEBUG
> case VIDIOC_DBG_G_REGISTER:
>
> > if (!has_unsubscribe_event)
> > assign v4l2_event_subdev_unsubscribe as default .unsubscribe ops (somehow)
> >
> >
> > Or maybe v4l2_subdev_init_finalize() it's too late?
> > I'm completely wrong? What do you think?
>
> I like v4l2_subdev_init_finalize() as we're pushing all subdev drivers
> to use it, so it's an extra incentive.
>
> > > Well :)
> > > Not every subdev drivers, but only the ones I'm testing.
> > >
> > > Yesterday I was playing with ov5645 :) And I got:
> > >
> > > v4l2-compliance -d /dev/v4l-subdev1
> > >
> > > test VIDIOC_G/S/TRY_EXT_CTRLS: OK
> > > fail: v4l2-test-controls.cpp(1108): subscribe event for control 'User Controls' failed
> > >
> > > Joke apart fully agree and thanks for your hint!
> > > I will take a look :)
> > >
> > > > > ov5645->pad.flags = MEDIA_PAD_FL_SOURCE;
> > > > > ov5645->sd.dev = &client->dev;
> > > > > ov5645->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
>
> --
> Regards,
>
> Laurent Pinchart
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