Re: [PATCH v10 1/4] gpu: drm: separate panel orientation property creating and value setting

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 5/30/22 10:19, Hsin-Yi Wang wrote:
> drm_dev_register() sets connector->registration_state to
> DRM_CONNECTOR_REGISTERED and dev->registered to true. If
> drm_connector_set_panel_orientation() is first called after
> drm_dev_register(), it will fail several checks and results in following
> warning.
> 
> Add a function to create panel orientation property and set default value
> to UNKNOWN, so drivers can call this function to init the property earlier
> , and let the panel set the real value later.
> 
> [    4.480976] ------------[ cut here ]------------
> [    4.485603] WARNING: CPU: 5 PID: 369 at drivers/gpu/drm/drm_mode_object.c:45 __drm_mode_object_add+0xb4/0xbc
> <snip>
> [    4.609772] Call trace:
> [    4.612208]  __drm_mode_object_add+0xb4/0xbc
> [    4.616466]  drm_mode_object_add+0x20/0x2c
> [    4.620552]  drm_property_create+0xdc/0x174
> [    4.624723]  drm_property_create_enum+0x34/0x98
> [    4.629241]  drm_connector_set_panel_orientation+0x64/0xa0
> [    4.634716]  boe_panel_get_modes+0x88/0xd8
> [    4.638802]  drm_panel_get_modes+0x2c/0x48
> [    4.642887]  panel_bridge_get_modes+0x1c/0x28
> [    4.647233]  drm_bridge_connector_get_modes+0xa0/0xd4
> [    4.652273]  drm_helper_probe_single_connector_modes+0x218/0x700
> [    4.658266]  drm_mode_getconnector+0x1b4/0x45c
> [    4.662699]  drm_ioctl_kernel+0xac/0x128
> [    4.666611]  drm_ioctl+0x268/0x410
> [    4.670002]  drm_compat_ioctl+0xdc/0xf0
> [    4.673829]  __arm64_compat_sys_ioctl+0xc8/0x100
> [    4.678436]  el0_svc_common+0xf4/0x1c0
> [    4.682174]  do_el0_svc_compat+0x28/0x3c
> [    4.686088]  el0_svc_compat+0x10/0x1c
> [    4.689738]  el0_sync_compat_handler+0xa8/0xcc
> [    4.694171]  el0_sync_compat+0x178/0x180
> [    4.698082] ---[ end trace b4f2db9d9c88610b ]---
> [    4.702721] ------------[ cut here ]------------
> [    4.707329] WARNING: CPU: 5 PID: 369 at drivers/gpu/drm/drm_mode_object.c:243 drm_object_attach_property+0x48/0xb8
> <snip>
> [    4.833830] Call trace:
> [    4.836266]  drm_object_attach_property+0x48/0xb8
> [    4.840958]  drm_connector_set_panel_orientation+0x84/0xa0
> [    4.846432]  boe_panel_get_modes+0x88/0xd8
> [    4.850516]  drm_panel_get_modes+0x2c/0x48
> [    4.854600]  panel_bridge_get_modes+0x1c/0x28
> [    4.858946]  drm_bridge_connector_get_modes+0xa0/0xd4
> [    4.863984]  drm_helper_probe_single_connector_modes+0x218/0x700
> [    4.869978]  drm_mode_getconnector+0x1b4/0x45c
> [    4.874410]  drm_ioctl_kernel+0xac/0x128
> [    4.878320]  drm_ioctl+0x268/0x410
> [    4.881711]  drm_compat_ioctl+0xdc/0xf0
> [    4.885536]  __arm64_compat_sys_ioctl+0xc8/0x100
> [    4.890142]  el0_svc_common+0xf4/0x1c0
> [    4.893879]  do_el0_svc_compat+0x28/0x3c
> [    4.897791]  el0_svc_compat+0x10/0x1c
> [    4.901441]  el0_sync_compat_handler+0xa8/0xcc
> [    4.905873]  el0_sync_compat+0x178/0x180
> [    4.909783] ---[ end trace b4f2db9d9c88610c ]---
> 
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> Reviewed-by: Sean Paul <seanpaul@chromium.org>
> ---
> v9->v10: rebase to latest linux-next.
> v9: https://patchwork.kernel.org/project/linux-mediatek/patch/20220318074825.3359978-2-hsinyi@chromium.org/
> v8: https://patchwork.kernel.org/project/linux-mediatek/patch/20220208084234.1684930-1-hsinyi@chromium.org/
> v7: https://patchwork.kernel.org/project/linux-mediatek/patch/20220208073714.1540390-1-hsinyi@chromium.org/
> ---
>  drivers/gpu/drm/drm_connector.c | 58 +++++++++++++++++++++++++--------
>  include/drm/drm_connector.h     |  2 ++
>  2 files changed, 47 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 1c48d162c77e..d68cc78f6684 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -1252,7 +1252,7 @@ static const struct drm_prop_enum_list dp_colorspaces[] = {
>   *	INPUT_PROP_DIRECT) will still map 1:1 to the actual LCD panel
>   *	coordinates, so if userspace rotates the picture to adjust for
>   *	the orientation it must also apply the same transformation to the
> - *	touchscreen input coordinates. This property is initialized by calling
> + *	touchscreen input coordinates. This property value is set by calling
>   *	drm_connector_set_panel_orientation() or
>   *	drm_connector_set_panel_orientation_with_quirk()
>   *
> @@ -2310,8 +2310,8 @@ EXPORT_SYMBOL(drm_connector_set_vrr_capable_property);
>   * @connector: connector for which to set the panel-orientation property.
>   * @panel_orientation: drm_panel_orientation value to set
>   *
> - * This function sets the connector's panel_orientation and attaches
> - * a "panel orientation" property to the connector.
> + * This function sets the connector's panel_orientation value. If the property
> + * doesn't exist, it will try to create one.
>   *
>   * Calling this function on a connector where the panel_orientation has
>   * already been set is a no-op (e.g. the orientation has been overridden with
> @@ -2343,18 +2343,13 @@ int drm_connector_set_panel_orientation(
>  
>  	prop = dev->mode_config.panel_orientation_property;
>  	if (!prop) {
> -		prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
> -				"panel orientation",
> -				drm_panel_orientation_enum_list,
> -				ARRAY_SIZE(drm_panel_orientation_enum_list));
> -		if (!prop)
> +		if (drm_connector_init_panel_orientation_property(connector) < 0)
>  			return -ENOMEM;
> -
> -		dev->mode_config.panel_orientation_property = prop;
> +		prop = dev->mode_config.panel_orientation_property;
>  	}
>  
> -	drm_object_attach_property(&connector->base, prop,
> -				   info->panel_orientation);
> +	drm_object_property_set_value(&connector->base, prop,
> +				      info->panel_orientation);
>  	return 0;
>  }
>  EXPORT_SYMBOL(drm_connector_set_panel_orientation);
> @@ -2362,7 +2357,7 @@ EXPORT_SYMBOL(drm_connector_set_panel_orientation);
>  /**
>   * drm_connector_set_panel_orientation_with_quirk - set the
>   *	connector's panel_orientation after checking for quirks
> - * @connector: connector for which to init the panel-orientation property.
> + * @connector: connector for which to set the panel-orientation property.
>   * @panel_orientation: drm_panel_orientation value to set
>   * @width: width in pixels of the panel, used for panel quirk detection
>   * @height: height in pixels of the panel, used for panel quirk detection
> @@ -2389,6 +2384,43 @@ int drm_connector_set_panel_orientation_with_quirk(
>  }
>  EXPORT_SYMBOL(drm_connector_set_panel_orientation_with_quirk);
>  
> +/**
> + * drm_connector_init_panel_orientation_property -
> + * 	create the connector's panel orientation property
> + *
> + * This function attaches a "panel orientation" property to the connector
> + * and initializes its value to DRM_MODE_PANEL_ORIENTATION_UNKNOWN.
> + *
> + * The value of the property can be set by drm_connector_set_panel_orientation()
> + * or drm_connector_set_panel_orientation_with_quirk() later.
> + *
> + * Returns:
> + * Zero on success, negative errno on failure.
> + */
> +int drm_connector_init_panel_orientation_property(
> +	struct drm_connector *connector)
> +{
> +	struct drm_device *dev = connector->dev;
> +	struct drm_property *prop;
> +
> +	if(dev->mode_config.panel_orientation_property)
> +		return 0;
> +
> +	prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE,
> +			"panel orientation",
> +			drm_panel_orientation_enum_list,
> +			ARRAY_SIZE(drm_panel_orientation_enum_list));
> +	if (!prop)
> +		return -ENOMEM;
> +
> +	dev->mode_config.panel_orientation_property = prop;
> +	drm_object_attach_property(&connector->base, prop,
> +				   DRM_MODE_PANEL_ORIENTATION_UNKNOWN);

DRM_MODE_PANEL_ORIENTATION_UNKNOWN is -1 which is not a valid value
for an enum. IOW when the panel-orientation is DRM_MODE_PANEL_ORIENTATION_UNKNOWN
then the property should not be created on the drm-connector object at all.

Which brings us back to what I said in reply to the coverletter,
it seems that you have a probe ordering problem here; and fixing that
issue would make this patch-set unnecessary.

Regards,

Hans



> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_connector_init_panel_orientation_property);
> +
>  static const struct drm_prop_enum_list privacy_screen_enum[] = {
>  	{ PRIVACY_SCREEN_DISABLED,		"Disabled" },
>  	{ PRIVACY_SCREEN_ENABLED,		"Enabled" },
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 3ac4bf87f257..f0681091c617 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1802,6 +1802,8 @@ int drm_connector_set_panel_orientation_with_quirk(
>  	struct drm_connector *connector,
>  	enum drm_panel_orientation panel_orientation,
>  	int width, int height);
> +int drm_connector_init_panel_orientation_property(
> +	struct drm_connector *connector);
>  int drm_connector_attach_max_bpc_property(struct drm_connector *connector,
>  					  int min, int max);
>  void drm_connector_create_privacy_screen_properties(struct drm_connector *conn);


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