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From:   Mark Yacoub <markyacoub@chromium.org>
Date:   Mon, 16 May 2022 11:10:57 -0400
Message-ID: <CAJUqKUp2OGxexZDncNZu9NAsScWtFaZqGKzBt8yf0JFzSLvaWA@mail.gmail.com>
Subject: Re: [PATCH] drm: Add a debug message when getting a prop is missing
Cc:     seanpaul@chromium.org, markyacoub@google.com,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
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friendly ping :))

On Tue, May 10, 2022 at 2:28 PM Mark Yacoub <markyacoub@chromium.org> wrote:
>
> [Why]
> If a connector property is attached but
> drm_atomic_connector_get_property doesn't handle a case for it,
> modeteset will crash with a segfault without.
>
> [How]
> Add a debug message indicating that a connector property is not handled
> when user space is trying to read it.
>
> TEST=modetest
>
> Signed-off-by: Mark Yacoub <markyacoub@chromium.org>
> ---
>  drivers/gpu/drm/drm_atomic_uapi.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
> index acb1ee93d206..36b0f664dd80 100644
> --- a/drivers/gpu/drm/drm_atomic_uapi.c
> +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> @@ -884,6 +884,12 @@ drm_atomic_connector_get_property(struct drm_connector *connector,
>                 return connector->funcs->atomic_get_property(connector,
>                                 state, property, val);
>         } else {
> +               // LOG that the kernel is missing handling this property as a case here.
> +               drm_dbg_atomic(
> +                       dev,
> +                       "[CONNECTOR:%d:%s] Get Property [PROP:%d:%s] is not handled\n",
> +                       connector->base.id, connector->name, property->base.id,
> +                       property->name);
>                 return -EINVAL;
>         }
>
> --
> 2.36.0.512.ge40c2bad7a-goog
>