[PATCH] drm/ast: Add detect function support

[PATCH] drm/ast: Add detect function support

[ainux.wang]

From: Ainux <ainux.wang@gmail.com>

The existence of the connector cannot be detected,
so add the detect function to support.

Signed-off-by: Ainux <ainux.wang@gmail.com>
---
 drivers/gpu/drm/ast/ast_drv.c  |  2 ++
 drivers/gpu/drm/ast/ast_mode.c | 19 ++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 5aa452b4efe6..6698bbc405e3 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -128,6 +128,8 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	drm_fbdev_generic_setup(dev, 32);
 
+	drm_kms_helper_poll_init(dev);
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index 36d9575aa27b..b4dd4c29b353 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1293,6 +1293,21 @@ static enum drm_mode_status ast_mode_valid(struct drm_connector *connector,
 	return flags;
 }
 
+static enum drm_connector_status ast_connector_detect(struct drm_connector
+						   *connector, bool force)
+{
+	int r;
+	enum drm_connector_status ret = connector_status_connected;
+
+	r = ast_get_modes(connector);
+	if (r)
+		ret = connector_status_connected;
+	else
+		ret = connector_status_disconnected;
+
+	return ret;
+}
+
 static void ast_connector_destroy(struct drm_connector *connector)
 {
 	struct ast_connector *ast_connector = to_ast_connector(connector);
@@ -1307,6 +1322,7 @@ static const struct drm_connector_helper_funcs ast_connector_helper_funcs = {
 
 static const struct drm_connector_funcs ast_connector_funcs = {
 	.reset = drm_atomic_helper_connector_reset,
+	.detect = ast_connector_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.destroy = ast_connector_destroy,
 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
@@ -1334,7 +1350,8 @@ static int ast_connector_init(struct drm_device *dev)
 	connector->interlace_allowed = 0;
 	connector->doublescan_allowed = 0;
 
-	connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+	connector->polled = DRM_CONNECTOR_POLL_CONNECT |
+						DRM_CONNECTOR_POLL_DISCONNECT;
 
 	drm_connector_attach_encoder(connector, encoder);
 
-- 
2.18.1

Re: [PATCH] drm/ast: Add detect function support

[Thomas Zimmermann]

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Hi,

thanks for the patch.

Am 25.05.21 um 03:55 schrieb ainux.wang@gmail.com:
> From: Ainux <ainux.wang@gmail.com>
> 
> The existence of the connector cannot be detected,
> so add the detect function to support.
> 
> Signed-off-by: Ainux <ainux.wang@gmail.com>
> ---
>   drivers/gpu/drm/ast/ast_drv.c  |  2 ++
>   drivers/gpu/drm/ast/ast_mode.c | 19 ++++++++++++++++++-
>   2 files changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
> index 5aa452b4efe6..6698bbc405e3 100644
> --- a/drivers/gpu/drm/ast/ast_drv.c
> +++ b/drivers/gpu/drm/ast/ast_drv.c
> @@ -128,6 +128,8 @@ static int ast_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>   
>   	drm_fbdev_generic_setup(dev, 32);
>   
> +	drm_kms_helper_poll_init(dev);
> +

I think this is too late. Rather put it at the end of 
ast_mode_config_init(). [1]

>   	return 0;
>   }
>   
> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
> index 36d9575aa27b..b4dd4c29b353 100644
> --- a/drivers/gpu/drm/ast/ast_mode.c
> +++ b/drivers/gpu/drm/ast/ast_mode.c
> @@ -1293,6 +1293,21 @@ static enum drm_mode_status ast_mode_valid(struct drm_connector *connector,
>   	return flags;
>   }
>   
> +static enum drm_connector_status ast_connector_detect(struct drm_connector
> +						   *connector, bool force)
> +{
> +	int r;
> +	enum drm_connector_status ret = connector_status_connected;
> +
> +	r = ast_get_modes(connector);
> +	if (r)
> +		ret = connector_status_connected;
> +	else
> +		ret = connector_status_disconnected;
> +
> +	return ret;


As a side note: VGA is not hotplug-able, but expected to always be 
connected. Ideally we could detect this, but it's unreliable AFAIK.


Rather use:

  r = ast_get_modes()
  if (r < 0)
     return connector_status_disconnected

   return connector_status_connected

So it's disconnected if there was an error in ast_get_modes().

Best regards
Thomas

[1] 
https://elixir.bootlin.com/linux/v5.12/source/drivers/gpu/drm/ast/ast_mode.c#L1171

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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