Hi Laurent,
On Fri, Sep 15, 2023 at 02:30:12PM +0300, Laurent Pinchart wrote:
> 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 ?
Ah, I think I misunderstood your earlier question.
The sensor may be left powered off for probe if the device's _DSC object
evaluates to 4. See Documentation/firmware-guide/acpi/non-d0-probe.rst for
more information.
>
> > > > + 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,
Sakari Ailus
