Hi Nikita,
Thank you for the patch.
On Sat, Dec 25, 2021 at 09:31:51AM +0300, Nikita Yushchenko wrote:
> Hotplug events reported by bridge drivers over drm_bridge_hpd_notify()
> get ignored unless somebody calls drm_bridge_hpd_enable(). When the
> connector for the bridge is bridge_connector, such a call is done from
> drm_bridge_connector_enable_hpd().
>
> However drm_bridge_connector_enable_hpd() is never called on init paths,
> documentation suggests that it is intended for suspend/resume paths.
Hmmmm... I'm in two minds about this. The problem description is
correct, but I wonder if HPD should be enabled unconditionally here, or
if this should be left to display drivers to control.
drivers/gpu/drm/imx/dcss/dcss-kms.c enables HPD manually at init time,
other drivers don't.
It feels like this should be under control of the display controller
driver, but I can't think of a use case for not enabling HPD at init
time. Any second opinion from anyone ?
> In result, once encoders are switched to bridge_connector,
> bridge-detected HPD stops working.
>
> This patch adds a call to that API on init path.
>
> This fixes HDMI HPD with rcar-du + adv7513 case when adv7513 reports HPD
> events via interrupts.
>
> Fixes: c24110a8fd09 ("drm: rcar-du: Use drm_bridge_connector_init() helper")
> Signed-off-by: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_bridge_connector.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_bridge_connector.c b/drivers/gpu/drm/drm_bridge_connector.c
> index 791379816837..4f20137ef21d 100644
> --- a/drivers/gpu/drm/drm_bridge_connector.c
> +++ b/drivers/gpu/drm/drm_bridge_connector.c
> @@ -369,8 +369,10 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
> connector_type, ddc);
> drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);
>
> - if (bridge_connector->bridge_hpd)
> + if (bridge_connector->bridge_hpd) {
> connector->polled = DRM_CONNECTOR_POLL_HPD;
> + drm_bridge_connector_enable_hpd(connector);
> + }
> else if (bridge_connector->bridge_detect)
> connector->polled = DRM_CONNECTOR_POLL_CONNECT
> | DRM_CONNECTOR_POLL_DISCONNECT;
--
Regards,
Laurent Pinchart
