Re: [PATCH v2 3/4] media: v4l2-async: Log message in case of heterogenous fwnode match

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Laurent,

On Wed, Mar 18, 2020 at 1:26 AM Laurent Pinchart
<laurent.pinchart+renesas@ideasonboard.com> wrote:
> When a notifier supplies a device fwnode and a subdev supplies an
> endpoint fwnode, incorrect matches may occur if multiple subdevs
> correspond to the same device fwnode. This can't be handled
> transparently in the framework, and requires the notifier to switch to
> endpoint fwnodes. Log a message to notify of this problem. A second
> message is added to help accelerating the transition to endpoint
> matching.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Thanks for your patch!

> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c
> @@ -113,7 +114,28 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
>
>         fwnode_handle_put(dev_fwnode);
>
> -       return dev_fwnode == other_fwnode;
> +       if (dev_fwnode != other_fwnode)
> +               return false;
> +
> +       /*
> +        * We have an heterogenous match. Retrieve the struct device of the
> +        * side that matched on a device fwnode to print its driver name.
> +        */
> +       if (sd_fwnode_is_ep)
> +               dev = notifier->v4l2_dev ? notifier->v4l2_dev->dev
> +                   : notifier->sd->dev;
> +       else
> +               dev = sd->dev;
> +
> +       if (dev && dev->driver) {
> +               if (sd_fwnode_is_ep)
> +                       dev_info(dev, "Driver %s uses device fwnode, incorrect match may occur\n",
> +                                dev->driver->name);

I think that deserves a dev_warn().

> +               dev_info(dev, "Consider updating driver %s to match on endpoints\n",
> +                        dev->driver->name);

And dev_notice(), while at it ;-)

> +       }
> +
> +       return true;
>  }

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds