linux-kernel - Re: [PATCH] drm: xlnx: zynqmp_dpsub: also call drm_helper_hpd_irq

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Message-ID: <20240924184335.GJ30551@pendragon.ideasonboard.com>
Date: Tue, 24 Sep 2024 21:43:35 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: lists@...ffen.cc
Cc: dri-devel@...ts.freedesktop.org,
	Steffen Dirkwinkel <s.dirkwinkel@...khoff.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
	Michal Simek <michal.simek@....com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm: xlnx: zynqmp_dpsub: also call
 drm_helper_hpd_irq_event

Hi Steffen,

Thank you for the patch.

On Mon, Sep 23, 2024 at 09:48:03AM +0200, lists@...ffen.cc wrote:
> From: Steffen Dirkwinkel <s.dirkwinkel@...khoff.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@...khoff.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