On Fri, Sep 15, 2023 at 10:09:37AM +0000, Sakari Ailus wrote:
> On Fri, Sep 15, 2023 at 12:42:39PM +0300, Laurent Pinchart wrote:
> > On Fri, Sep 15, 2023 at 10:28:07AM +0300, Sakari Ailus wrote:
> > > Enable runtime PM before registering the async sub-device as the ipu
> > > bridge may try to resume the device immediately after the async sub-device
> >
> > I wouldn't mention ipu bridge there, as this driver is not specific to a
> > particular CSI-2 receiver.
> >
> > > has been registered. If runtime PM is still disabled, this will fail.
> > >
> > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > > ---
> > > drivers/media/i2c/ov2740.c | 14 ++++++++------
> > > 1 file changed, 8 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c
> > > index 41d4f85470fd..319dc00e47b4 100644
> > > --- a/drivers/media/i2c/ov2740.c
> > > +++ b/drivers/media/i2c/ov2740.c
> > > @@ -1172,6 +1172,12 @@ static int ov2740_probe(struct i2c_client *client)
> > > goto probe_error_v4l2_ctrl_handler_free;
> > > }
> > >
> > > + /* Set the device's state to active if it's in D0 state. */
> > > + if (full_power)
> > > + pm_runtime_set_active(&client->dev);
> >
> > I wonder why we need this in drivers. If ACPI has powered the device on
> > prior to calling probe(), couldn't it also set the PM runtime state
> > accordingly ?
>
> What happens here is that the ipu bridge creates a VCM device and it
> resumes the related sensor before instantiating that device (see
> ipu_bridge_instantiate_vcm_work()). However this may take place already
> right after registering the async sub-device. Resuming the sensor will fail
> if runtime PM isn't enabled.
>
> I'll add something along these lines to the commit message.
I understand this, but that doesn't answer my question :-) Why is there
a need to call pm_runtime_set_active(), couldn't it be done somewhere in
common code ?
> > > + pm_runtime_enable(&client->dev);
> > > + pm_runtime_idle(&client->dev);
> > > +
> >
> > With the commit message fixed,
> >
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> Thank you.
>
> > > ret = v4l2_async_register_subdev_sensor(&ov2740->sd);
> > > if (ret < 0) {
> > > dev_err_probe(dev, ret, "failed to register V4L2 subdev\n");
> > > @@ -1182,16 +1188,12 @@ static int ov2740_probe(struct i2c_client *client)
> > > if (ret)
> > > dev_warn(&client->dev, "register nvmem failed, ret %d\n", ret);
> > >
> > > - /* Set the device's state to active if it's in D0 state. */
> > > - if (full_power)
> > > - pm_runtime_set_active(&client->dev);
> > > - pm_runtime_enable(&client->dev);
> > > - pm_runtime_idle(&client->dev);
> > > -
> > > return 0;
> > >
> > > probe_error_media_entity_cleanup:
> > > media_entity_cleanup(&ov2740->sd.entity);
> > > + pm_runtime_disable(&client->dev);
> > > + pm_runtime_set_suspended(&client->dev);
> > >
> > > probe_error_v4l2_ctrl_handler_free:
> > > v4l2_ctrl_handler_free(ov2740->sd.ctrl_handler);
--
Regards,
Laurent Pinchart
