Re: [PATCH] drm: xlnx: zynqmp_dpsub: also call drm_helper_hpd_irq_event

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Steffen,

Thank you for the patch.

On Mon, Sep 23, 2024 at 09:48:03AM +0200, lists@steffen.cc wrote:
> From: Steffen Dirkwinkel <s.dirkwinkel@beckhoff.com>
> 
> With hpd going through the bridge as of commit eb2d64bfcc17
> ("drm: xlnx: zynqmp_dpsub: Report HPD through the bridge")
> we don't get hotplug events in userspace on zynqmp hardware.
> Also sending hotplug events with drm_helper_hpd_irq_event works.

Why does the driver need to call both drm_helper_hpd_irq_event() and
drm_bridge_hpd_notify() ? The latter should end up calling
drm_kms_helper_connector_hotplug_event(), which is the same function
that drm_helper_hpd_irq_event() calls.

> Fixes: eb2d64bfcc17 ("drm: xlnx: zynqmp_dpsub: Report HPD through the bridge")
> Signed-off-by: Steffen Dirkwinkel <s.dirkwinkel@beckhoff.com>
> ---
>  drivers/gpu/drm/xlnx/zynqmp_dp.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> index 1846c4971fd8..cb823540a412 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> @@ -17,6 +17,7 @@
>  #include <drm/drm_fourcc.h>
>  #include <drm/drm_modes.h>
>  #include <drm/drm_of.h>
> +#include <drm/drm_probe_helper.h>
>  
>  #include <linux/clk.h>
>  #include <linux/delay.h>
> @@ -1614,6 +1615,9 @@ static void zynqmp_dp_hpd_work_func(struct work_struct *work)
>  					    hpd_work.work);
>  	enum drm_connector_status status;
>  
> +	if (dp->bridge.dev)
> +		drm_helper_hpd_irq_event(dp->bridge.dev);
> +
>  	status = zynqmp_dp_bridge_detect(&dp->bridge);
>  	drm_bridge_hpd_notify(&dp->bridge, status);
>  }

-- 
Regards,

Laurent Pinchart